Add shareasale tracking code to Drupal Ubercart order completion page

<?php
 
function phptemplate_preprocess_page(&$vars) {
 
	if(drupal_get_path_alias($_GET['q']) == 'cart/checkout/complete') {
 
		// Getting order id
		preg_match("^Your order number is (\d*).^", $vars['content'], $matches);
		$order_id = $matches[1];
 
		$order = uc_order_load($order_id);
 
		$vars['closure'] .= '<img src="https://shareasale.com/sale.cfm?amount=' . $order->order_total . '&tracking=' . $order->order_id . '&transtype=sale&merchantID=XXXXXX" width="1" height="1">';
 
	}
}
 
?>