MarxistI've been huge into German music for --- wow almost 20 years lol. I salute your tastes ;)
Rosetta stone is very expensive - but you can, on ebay and etc, often find used copies of "outdated" versions rather cheaply - and also most libraries will pass you the stuff on inter-library loan if need be. There's also you know... other means.
Another option, is find a university that teaches courses in Polish - e-mail the professor, tell them you'd like to learn Polish but wherever you are there aren't any good options to learn Polish. After a few days they should hit you up with *something*. I'm sure there have to be free websites that help with some stuff. That's how I went about learning Russian lol - just emailed a bunch of Russian language profs asking how a strapping young gent. like myself could learn Russian without it being offered nearby and without travel being an option. I got plenty of good recommendations and often free resources.
Thanks for the suggestion, I know for a fact that there are Italian and Dutch offered down at the community college I live near, but I don't know about polish. Do you speak german?