Actually if you still need a good program I got one for you.

Whenever I need to convert .wma or .mp3 files to either one I use a program call ImToo. It has real good quality conversions. You can download the trial now it says you can only use it 3 times. All that means is 3 files at a time, then you gotta close it, and re-open it. A minor pain for a good program that's free.