How to integrate third party tracking system

Hi,

I have read this topic again and again, but i think i miss something.

Which file should i put my img code in?

Can i just use this code in the file or:

$app =& JFactory::getApplication();
$order_id = $app->getUserState(HIKASHOP_COMPONENT.'.order_id');
$orderClass = hikashop::get('class.order');
$order = $orderClass->get($order_id);
echo '<img src=" www.partner-ads.com/dk/leadtrack.php?pro...price_value_with_tax " width=1 height=1>';

Hope someone can help, because i really not understand this.