How to view the landing page of a subscription in Joomla 1.5.22?

Question

I have several landing pages with subscription button, and there is already PHP code on them to show me the landing page and source of the subscriber on the backend of Joomla. I am creating a new landing page and would like to update the code so that I can see that the subscribers would come from this page. Here's the code:

<?php
  if (empty($_GET['lang'])
      || !in_array($_GET['lang'],array('de','en'))) {

    $_GET['lang'] = 'en';    
  }
  $language = $_GET['lang'];

  $text = array(

               );

  $redirect = '/see-properties?utm_source=Other&utm_medium=CPC&utm_content=LP1-o&utm_campaign=LP1-o';
  $lists = '1,45';
  $website = 'http://www.rubinarealestate.com/?utm_source=Google&utm_medium=CPC&utm_content=LP1-source&utm_campaign=LP1-source';

  if (strpos($_SERVER['REQUEST_URI'], '/linkedin/') !== false) {
    $redirect = '/see-properties?utm_source=Linkedin&utm_medium=CPC&utm_content=LP1&utm_campaign=LP1';
    $lists .= ',11';
    $website = 'http://www.rubinarealestate.com/?utm_source=Linkedin&utm_medium=CPC&utm_content=LP1-lkdin&utm_campaign=LP1-lkdin';
  }
  else if (strpos($_SERVER['REQUEST_URI'], '/adwords/') !== false) {
    $redirect = '/see-properties?utm_source=Adwords&utm_medium=CPC&utm_content=LP1-google&utm_campaign=LP1-google';
    $lists .= ',12';
    $website = 'http://www.rubinarealestate.com/?utm_source=Google&utm_medium=CPC&utm_content=LP1-google&utm_campaign=LP1-google';
  }
  else if (strpos($_SERVER['REQUEST_URI'], '/social/') !== false) {
    $lists .= ',11';
  }
?>

Any help is appreciated! Thanks!