It sounds like you would just need to create a new template page (not a module) and add the Google code there. You'll likely need to point the search form to the URL of the new CMPS page you created as well... Assuming Google uses a form for the search box, it would need to look something like this:
(replace page_identifier_here with whatever you use for the Page Identifier setting for the new template page you create).
<form action="index.php" method="post">
<input type="hidden" name="pageid" value="page_identifier_here" />