If you want the image to show after your title, that's where you'll need to place this code:
<?php it_exchange( 'product', 'featured-image', array( 'size' => 'thumbnail' ) ); ?>
The example in the codex is for the Twenty Eleven theme. Your theme's archive.php/category.php may look different, so you'll need to determine where it goes.
The email address is already asked for in the registration (screenshot taken from your site):
If you have further questions about the registration form, please start a new thread as this is off the topic of this post.