I would recommend Musicmatch Jukebox (available as a free download - just search in google) for all these needs. It has a convert files function which will let you change MP3's to wav (and vice versa) and will allow you to change the compression rates on your MP3's.
What you want to do is known as ripping.
If you go to a good software download site such as ZDnet.com and do a search for cd ripper you should find plenty - both free and shareware. Most of them do a similar job.
http://downloads-zdnet.com.com/3120-20-0.html?qt=c d+ripper&tg=dl-2001