Please go easy on me if there is a thread (or more than one) out there on this topic already, but i did search and have not found the info i need.

I have been living in Switzerland for 4 months on a B permit, prior to that i was working in the US. So i have a w-2 Form from my US employer for most of 2009. But i received income in Basel from September onwards. I haven't got a clue how to file my taxes in the US. I dont want to end up owing when really i should be getting a return. I am filing as single. Does anyone have any advice on how to proceed? Any help is appreciated.