a> Get a Shure SM57 instead....its better for instrument miking...although its almost the same mic as the SM58.. More info here: http://www.gearslutz.com/board/low-e...sm57-sm58.html
b> Save money on the card...buy an M-Audio 2496...and put the extra money into a good pair of monitors.
c> Most low end monitors are crap. Sad but true. The low end M-audios are the worst of the bunch. The only decent sub-10k speakers for mixing are the smaller AudioEngines IMHO. Make do with some good headphones (Sony MDR7506) now and save up for better monitors in the 20-30k range....and think twice about mixing on monitors in an un-acoustically-treated room... some info here: http://www.soundonsound.com/sos/jan0...headphones.htm
What preamps are you thinking of getting?
If its just a small project you are thinking of mixing...go to a small studio nearby and get it done...its much more convenient and cost effective.
If on the other hand you want to set up a small project studio where you will work from pretty often....save up some more money and have a lot of patience...
All the best!!
Music Has the Right to Children