Theres not much that can be done about people like this. I know a bunch of girls who are on hush-hush.com without them even knowing about it. Hush-hush will do nothing about it because they simply don't care.
All you can really do is watermark and tag (place a URL that cannot be removed, ie: large text with a transparency) every single image
I dunno.. sucks though, I'm sorry for you.