music match jukebox can convert mp3 to wav...it costs nothing and is available on their website....just be careful with your install so as not to make MMJB the main player on your machine.....I use it exclusively for mp3 since cakewalk takes a ridiculously long time to do any kind of save except .wrk
You could try the conversion program called "CDex" at www.cdex.n3.net
I have had excellent results with this program. It's freeware. Nice & clean with no extra software baggage. Fast. Also converts CD tracks to WAV or MP3 as well as WAV to MP3.
I think you can't do that in Cakewalk so. At least not easy. so I suggest you get another software to convert your audio files. I use Steinberg's Wavelab 3.03 but there are plenty of free softwares in the net that can do that...so just pick one and you're there..