Converting "Add to Cart" to link to an outside URL

<?php echo $btn_add; ?>

<input type="button" onclick="window.location='<?php echo $item->product_url; ?>'; return false;" value="buy now"/>

<?php
/**
* @package HikaShop for Joomla!
* @version 2.3.0
* @author hikashop.com
* @copyright (C) 2010-2014 HIKARI SOFTWARE. All rights reserved.
* @license GNU/GPLv3 www.gnu.org/licenses/gpl-3.0.html
*/
defined('_JEXEC') or die('Restricted access');
?><?php

if($this->config->get('show_quantity_field')==-2){
$this->params->set('show_quantity_field',$this->row->product_display_quantity_field);
}

$config =& hikashop_config();

$wishlistEnabled = $config->get('enable_wishlist', 1);
$hideForGuest = 1;
if(($config->get('hide_wishlist_guest', 1) && hikashop_loadUser() != null) || !$config->get('hide_wishlist_guest', 1)){
$hideForGuest = 0;
}

if(!isset($this->cart)) $this->cart = hikashop_get('helper.cart');
if(!empty($this->row->has_options)){
if($this->params->get('add_to_cart',1)) echo $this->cart->displayButton(JText::_('CHOOSE_OPTIONS'),'choose_options',$this->params,hikashop_completeLink('product&task=show&product_id='.$this->row->product_id.'&name='.$this->row->alias.$this->itemid.$this->category_pathway),'window.location = \''.str_replace("'","\'",hikashop_completeLink('product&task=show&product_id='.$this->row->product_id.'&name='.$this->row->alias.$this->itemid.$this->category_pathway)).'\';return false;','');
}else{
$this->cart = hikashop_get('helper.cart');
$url = '';
$module_id = $this->params->get('from_module',0);
if(empty($this->ajax)){
$this->ajax = 'return hikashopModifyQuantity(\''.$this->row->product_id.'\',field,1,0,\'cart\','.$module_id.')';
}
if(@$this->row->product_sale_start || empty($this->element->main)){
$start_date = @$this->row->product_sale_start;
}else{
$start_date = $this->element->main->product_sale_start;
}
if(@$this->row->product_sale_end || empty($this->element->main)){
$end_date = @$this->row->product_sale_end;
}else{
$end_date = $this->element->main->product_sale_end;
}
$formName = ',0';
if (!$this->config->get('ajax_add_to_cart', 0) || ($this->config->get('show_quantity_field')>=2 && !@$this->element->product_id)) {
if(empty($this->formName)) {
if(@$this->row->product_id)
$formName = ',\'hikashop_product_form_'.$this->row->product_id.'_'.$this->params->get('main_div_name').'\'';
else
$formName = ',\'hikashop_product_form_'.$this->params->get('main_div_name').'\'';
} else {
$formName = $this->formName;
}
}
if($end_date && $end_date<time()){
?>
<span class="hikashop_product_sale_end">
<?php echo JText::_('ITEM_NOT_SOLD_ANYMORE'); ?>
</span>
<?php
}elseif($start_date && $start_date>time()){
?>
<span class="hikashop_product_sale_start">
<?php
echo JText::sprintf('ITEM_SOLD_ON_DATE',hikashop_getDate($start_date,$this->params->get('date_format','%d %B %Y')));
?>
</span>
<?php
}elseif(!$this->params->get('catalogue') && ($this->config->get('display_add_to_cart_for_free_products') || !empty($this->row->prices))){
if(@$this->row->product_min_per_order || empty($this->element->main)){
$min = @$this->row->product_min_per_order;
}else{
$min = @$this->element->main->product_min_per_order;
}
if(@$this->row->product_max_per_order || empty($this->element->main)){
$max = @$this->row->product_max_per_order;
}else{
$max = @$this->element->main->product_max_per_order;
}
if($min<=0){
$min=1;
}
$wishlistAjax = 'if(hikashopCheckChangeForm(\'item\''.$formName.')){ return hikashopModifyQuantity(\'' . (int)@$this->row->product_id . '\',field,1' . $formName . ',\'wishlist\','.$module_id.'); } else { return false; }';

if($this->row->product_quantity == -1 && !empty($this->element->main) && $this->element->main->product_quantity != -1){
$this->row->product_quantity = $this->element->main->product_quantity;
}
$btnType = 'add';
if($this->row->product_quantity==-1){
?>
<div class="hikashop_product_stock">
<?php
if($this->params->get('add_to_cart',1)){
?>
<input type="button" class="button btn" onClick="window.location='<?php echo $this->row->product_url; ?>'; return false;" value="comprar"/>
<?php
//echo $this->cart->displayButton(JText::_('ADD_TO_CART'), 'add', $this->params, $url, $this->ajax, '', $max, $min);
$btnType = 'wish';
}
if(hikashop_level(1) && $this->params->get('add_to_wishlist') && $wishlistEnabled && !$hideForGuest && $this->config->get('display_add_to_wishlist_for_free_products','1')){
echo '<div id="hikashop_add_wishlist">';
echo $this->cart->displayButton(JText::_('ADD_TO_WISHLIST'),$btnType,$this->params,$url,$wishlistAjax,'',$max,$min,'',false);
echo '</div>';
}
}elseif($this->row->product_quantity>0){
?>
<div class="hikashop_product_stock">
<?php
if($config->get('button_style','normal')=='css'){
echo '<br />';
}
if($max<=0 || $max>$this->row->product_quantity) $max = $this->row->product_quantity;
if($this->params->get('add_to_cart',1)){
echo $this->cart->displayButton(JText::_('ADD_TO_CART'),'add',$this->params,$url,$this->ajax,'',$max,$min);
$btnType = 'wish';
}
if(hikashop_level(1) && $this->params->get('add_to_wishlist') && $wishlistEnabled && !$hideForGuest && $this->config->get('display_add_to_wishlist_for_free_products','1')){
echo '<div id="hikashop_add_wishlist">';
echo $this->cart->displayButton(JText::_('ADD_TO_WISHLIST'),$btnType,$this->params,$url,$wishlistAjax,'',$max,$min,'',false);
echo '</div>';
}
}else{
?>
<div class="hikashop_product_no_stock">
<?php
$waitlist = $this->config->get('product_waitlist',0);
if(hikashop_level(1) && ($waitlist==2 || ($waitlist==1 && (!empty($this->element->main->product_waitlist) || !empty($this->element->product_waitlist))))){ ?>
</div><div id="hikashop_product_waitlist_main" class="hikashop_product_waitlist_main">
<?php
$empty='';
jimport('joomla.html.parameter');
$params = new HikaParameter($empty);
echo $this->cart->displayButton(JText::_('ADD_ME_WAITLIST'),'add_waitlist',$params,hikashop_completeLink('product&task=waitlist&cid='.$this->row->product_id),'window.location=\''.str_replace("'","\'",hikashop_completeLink('product&task=waitlist&cid='.$this->row->product_id)).'\';return false;');
}
if(hikashop_level(1) && $this->params->get('add_to_wishlist') && $wishlistEnabled && !$hideForGuest && $this->config->get('display_add_to_wishlist_for_free_products','1')){
echo '<div id="hikashop_add_wishlist">';
echo $this->cart->displayButton(JText::_('ADD_TO_WISHLIST'),'add',$this->params,$url,$wishlistAjax,'',@$this->row->product_max_per_order,1,'',false);
echo '</div>';
}
}?>
</div>
<?php
}elseif(hikashop_level(1) && $wishlistEnabled && $this->params->get('add_to_wishlist','1') && $this->config->get('display_add_to_wishlist_for_free_products','1') && !$hideForGuest && !$this->config->get('display_add_to_cart_for_free_products')){
$wishlistAjax = 'if(hikashopCheckChangeForm(\'item\''.$formName.')){ return hikashopModifyQuantity(\'' . (int)@$this->row->product_id . '\',field,1' . $formName . ',\'wishlist\','.$module_id.'); } else { return false; }';
echo '<div id="hikashop_add_wishlist">';
echo $this->cart->displayButton(JText::_('ADD_TO_WISHLIST'),'add',$this->params,$url,$wishlistAjax,'',@$this->row->product_max_per_order,1,'',false);
echo '</div>';
}
}

echo JText::_('NO_STOCK').'<br/>';

	<div class="hikashop_product_no_stock">
<?php

		if($this->row->product_quantity == 1 && JText::_('X_ITEM_IN_STOCK') != 'X_ITEM_IN_STOCK')
			$text = JText::sprintf('X_ITEM_IN_STOCK', $this->row->product_quantity);
		else
			$text = JText::sprintf('X_ITEMS_IN_STOCK', $this->row->product_quantity);

	<div class="hikashop_product_stock">
<?php

<input type="button" onclick="window.location='<?php echo $this->row->product_url; ?>'; return false;" value="buy now"/>

if($this->row->hikashop_product_url_main == 1)
{
$this->row->addtocartoption = 0;
}