Language / I want to learn Polish. Where to start? [180]

I am trying to find a good program to teach myself and my 2 teenage boys Polish. I have looked into TransparentLanguage and Rosetta Stone. My oldest son is currently using Rosetta Stone at his high school to learn German but after 5 months only knows a few words and no sentences and carries an A in his class. We are planning a trip to Poland for his senior trip, he has a desire to see where his great-great parents came from. So that gives us about 3 years to learn enough conversational Polish to make the trip. My grandfather knew Polish but for some reason didn't teach his children. We live in a very small community so the closest college that teaches Polish is 6 hours away. There is also a very small (less than 30 families) Polish community and no one speaks the language.