Hi,
You have to edit that code:
<table>
<tr>
<td rowspan="2">
<input id="hikashop_product_quantity_field_'.$i.'" type="text" value="'.JRequest::getInt('quantity',$min_quantity).'" class="hikashop_product_quantity_field" name="quantity" onchange="hikashopCheckQuantityChange(\'hikashop_product_quantity_field_'.$i.'\','.$max_quantity.','.$min_quantity.');" />
</td>
<td>
<a id="hikashop_product_quantity_field_change_plus_'.$i.'" class="hikashop_product_quantity_field_change_plus hikashop_product_quantity_field_change" href="#" onclick="return hikashopQuantityChange(\'hikashop_product_quantity_field_'.$i.'\',1,'.$max_quantity.','.$min_quantity.');">+</a>
</td>
<td rowspan="2">
'.$html.'
</td>
</tr>
<tr>
<td>
<a id="hikashop_product_quantity_field_change_minus_'.$i.'" class="hikashop_product_quantity_field_change_minus hikashop_product_quantity_field_change" href="#" onclick="return hikashopQuantityChange(\'hikashop_product_quantity_field_'.$i.'\',0,'.$max_quantity.','.$min_quantity.');">–</a>
</td>
</tr>
</table>
To putthe add to cart button out of the table, and then with some css properties you will be able to display it as you want.
Here is an example of code to replace the table.
<div class="hikashop_product_quantity_div hikashop_product_quantity_input_div_default">
<input id="hikashop_product_quantity_field_<?php echo $i; ?>" type="text" value="<?php echo JRequest::getInt('quantity',$min_quantity); ?>" class="hikashop_product_quantity_field" name="quantity" onchange="hikashopCheckQuantityChange('hikashop_product_quantity_field_<?php echo $i; ?>',<?php echo $max_quantity; ?>,<?php echo $min_quantity; ?>);" />
</div>
<div class="hikashop_product_quantity_div hikashop_product_quantity_change_div_default">
<div class="hikashop_product_quantity_change_div_plus_default">
<a id="hikashop_product_quantity_field_change_plus_<?php echo $i; ?>" class="hikashop_product_quantity_field_change_plus hikashop_product_quantity_field_change" href="#" onclick="return hikashopQuantityChange('hikashop_product_quantity_field_<?php echo $i; ?>',1,<?php echo $max_quantity; ?>,<?php echo $min_quantity; ?>);">+</a>
</div>
<div class="hikashop_product_quantity_change_div_minus_default">
<a id="hikashop_product_quantity_field_change_minus_<?php echo $i; ?>" class="hikashop_product_quantity_field_change_minus hikashop_product_quantity_field_change" href="#" onclick="return hikashopQuantityChange('hikashop_product_quantity_field_<?php echo $i; ?>',0,<?php echo $max_quantity; ?>,<?php echo $min_quantity; ?>);">–</a>
</div>
</div>
<div class="hikashop_product_quantity_div hikashop_product_quantity_add_to_cart_div hikashop_product_quantity_add_to_cart_div_default">
<?php echo $html; ?>
</div>
With the corresponding CSS:
.hikashop_product_quantity_div .hikashop_product_quantity_field{height:20px;}
.hikashop_product_quantity_div{display: inline-block;}
.hikashop_product_quantity_add_to_cart_div{display:block; vertical-align: top;}
.hikashop_product_quantity_field{text-align: center;}