Garageband and wmv videofiles

Is it poosible to get garageband to accept a wmv-videofile? I am new both to mac and garageband, and have just been given an wmv-file to score too. I have tried to install flip4mac but it doesn`t change anything.
Is there any free converter to a fileformat that Garageband can handle?
Thanks for any help - deadline is next week 🙂.

IMac Mac OS X (10.4.6)