Hey Crazy Katty, I was having a similar frustration when I accidently got a WMA when really I wanted the MP3. However I simple just found the MP3 of the file instead. Apparently in any sort of audio conversion you are likely to suffer significant quality loss, but I doubt in this case. Check out dBpowerAMP -
http://www.dbpoweramp.com/dmc.htm
- it's free by the way!
I've heard people saying that is a useful program and will do the conversion you require.
If that is no good however, you could also try downloading some of the programs from this site. However, they are not free, but they still have a trial period -
http://www.wma-mp3.com/