If you live in a major metropolitan area, there might be Polish agencies or groups that can help you. In my area, they teach Polish for credit at UIC (University of Illinois, Chicago) and for non credit at various local community colleges. You can also find tapes at the local library or even buy a set on your own. What does FILS mean? Ask your relatives to help, especially with your daughters. With children you start teaching a different language slowly. I learned some Lithuanian and Polish from my grandparents and great-grandma who spoke little English. I have the pronunciation down fairly well.
Another idea is to watch tv. We have a station in Chicago that has various different language programs. Even though I don't understand 99% of what they say sometimes, at others I get the idea. It helps.
Check out your local library for resources as well. Good luck.