I agree with Blue Bear. If you can't figure out how to connect a simple RCA to 1/8" cable, you have no business trying to do this yourself.
Your best bet, is to save up some more money and go to a professional studio. For $200, you won't get much in a studio, or at home. At best you'll get a crap recording, that you can't figure out how to burn to a CD to give to your other "homies" next week, and we'll have to listen to you piss and moan about not being able to work the software on your computer, until someone walks you through that.
Try reading your instruction manuals for your computer, I'm more than sure it'll tell you how to hook up your "dj mixer".
Good luck with all that. Really, I mean that.
No, wait. I don't.