Implementing Google Adwords Remarketing Custom Parameters for Opencart VQMOD

I am trying to implement adwords re-marketing tags into my site (www.fastforwardtime.co.uk). At first, I simply pasted the tag into the header.tpl file in order to get it to appear on every page. Then I noticed that if you want to use all of the features, you need to add custom parameters such as the product Id and value.



var google_tag_params = {
ecomm_prodid: 'REPLACE_WITH_VALUE',
ecomm_pagetype: 'REPLACE_WITH_VALUE',
ecomm_totalvalue: 'REPLACE_WITH_VALUE'
};



https://support.google.com/adwords/answer/3103357

I need some code written to grab the above parameters from opencart and dynamically paste them into the header file on each product page. A Vqmod script with no core file modifications would be ideal.

Opencart Version 1.5.2.1

Many thanks
Dave