Lesson I've learned is that even though the website seems to be dead, the project itself does not have to be. This is what I thought about http://gpl-violations.org/ and I was proven wrong and these guys are now looking at my case.
Another option is Software Freedom Law Center - http://www.softwarefreedom.org/. I've contacted them from the very beginning (about year ago) and got some useful hints, though now my contact seems to be gone (or simply too busy).
FSF also provides information how to proceed in case of license violation.
Maybe these hints will be also useful for somebody else and I hope they will help me as well.