I have a similar problem... an android app where users complain about a missing feature which is available when tapping Menu. Amazing how many android users don't know about that key!
I considered reporting the offending site to google (at least because they run adsense alongside) but I suppose that's useless in the long term... I need some kind of defense in my app!
My app uses a server backend to process images, so yes, pirated apps are a pain. I already have a free, less-featured ad-supported version. I could implement some sort of account authorization in the servers, but I think that would make the app more difficult to use.