So you want to re-record songs into a mp3, You can get Audacity:
http://audacity.sourceforge.net/
and download the LAME MP3 encoder. If you do this, Download Audacity and LAME MP3 encoder then open your origianal file. The go to file and export as Mp3 then it will ask you where LAME MP3 encoder and then open LAME MP3 encoder. Once you done that it should export as an mp3 file. I donno if this will help you but it's worth a shot.