[Plugin: Custom Contact Forms] Want to add logged in user email address

I tried to add the following code:

<?php global $display_name , $user_email;
get_currentuserinfo();

to the custom-contact-forms-front.php at the appropriate line
$mail->Subject = $admin_options[‘default_form_subject’] . ” From” . $user_email;

I’m trying to automatically add the users email address to the subject.. I get the “From” in the subject but not the users email address..

Any ideas or help would be great.. as I like this plugin

https://www.ads-software.com/extend/plugins/custom-contact-forms/