I have added Custom Fields to the Media Uploader in WP3.5. I am unsure of how to have that data displayed on the Attachment page.
There are a few different ways to get your values. One way is in the loop and another way is outside the loop. Here is a short code snippet that can be used to get them outside the loop
You will want to change the 'customField' in the last line above to the name of your custom field
You might also read up in the codex http://codex.wordpress.org/Custom_Fields
Here is another good source for you to look over http://vandelaydesign.com/blog/wordpress/custom-fields/
I would also try googling for some results on how to display them. There are tons of articles out there that will answer your question much faster than waiting for a response.