custom script in site.php

It took away days of my life and I can't get the invoice number, please help me someone!!!!

<?php
Am_Di::getInstance()->hook->add(Am_Event::ACCESS_AFTER_INSERT, 'myAccessHandler');

function myAccessHandler(Am_Event $event) {
$access = $event->getAccess();
$user = $event->getUser();
$invoice = $event->getInvoice();

if ($access->product_id == 5) {
$request = new Am_HttpRequest('http://www.flat-plan.com/teszt/test...>product_id.'&product_quantity='.$access->qty, Am_HttpRequest::METHOD_GET);
$request->send();
}
}
?>