So the full that you need is this one (with modifications of your google adwords data):
<?php
$app = JFactory::getApplication();
$app->enqueueMessage( JText::_('THANK_YOU_FOR_PURCHASE') );
$app = JFactory::getApplication();
$order_id = $app->getUserState('com_hikashop.order_id');
$orderClass = hikashop_get('class.order');
$order = $orderClass->loadFullOrder($order_id,false,false);
?>
<!-- Google Code -->
<script type="text/javascript">
/* <![CDATA[ */
var google_conversion_id = 1008879972;
var google_conversion_language = "es";
var google_conversion_format = "3";
var google_conversion_color = "ffffff";
var google_conversion_label = "dmuACJSH3R4Q5JKJ4QM";
var google_conversion_value = <?php echo round($order->order_full_price,2); ?>;
var google_remarketing_only = false;
/* ]]> */
</script>
<script type="text/javascript" src="//www.googleadservices.com/pagead/conversion.js">
</script>
<noscript>
<div style="display:inline;">
<img height="1" width="1" style="border-style:none;" alt="" src="//www.googleadservices.com/pagead/conversion/1008879972/?value=<?php echo round($order->order_full_price,2); ?>&label=dmuACJSH3R4Q5JKJ4QM&guid=ON&script=0"/>
</div>
</noscript>
You can add it in the file plugins/hikashoppayment/banktransfer/banktransfer_end.php in order to have it for the thank you page of the bank transfer payment method.
For your Joomla article, you'll need to use a plugin like sourcerer in order to add the code in a Joomla article.
If you need someone with more experience in PHP to do that for you, you can contact our partners for a quote:
www.hikashop.com/home/our-partners.html