Going after the host and registrar, since they're in less than friendly jurisdictions, isn't likely to be very fruitful.
Going after the billing may garner a bit more success, but they'll just move to other options.
In my experience, strictly as an observer, the most effective deterrent is a relentless pursuit on getting the files removed from the file sharing services. If the download links go dead quickly on a continual basis, those doing the uploading tend to move on to other sites that don't aggressively get the content removed.
A service that does that kind of work for you for a reasonable price
http://takedownpiracy.com/
I'd also recommend removeyourcontent.com but currently they aren't taking on new clients.