Renig,
to convert your file you can choose among a lot of programs, like Music Match Juke Box, Sound Forge, Quicktime and (I think) even Windows Media Player. Just choose a conversion rate above 128 Kb (for better sound quality) and you are set.
P.S.: maybe before converting you might want to normalize your .wav file to 90 dB (this way it would sound at a higher volume but without clipping. i.e. distorting).