O/T: recording music on a laptop

[buselmo]

well, i finally bought a laptop a couple of weeks ago (I R smart now! LOL) and i only bought it to record some shit i wrote years ago... downloaded Beatcraft and got the drum tracks set up, and i'm using audacity to record. I'm using a digitech RP500 for the guitar effects and it has a bass synthesizer which is pretty damn good... anyway, I have a sure SM58 mic that i was planning to use to record all the guitar sounds and vocals, but turns out i need a pre amp... in my country, you can only buy the huge PA systems if you need a pre amp... and i'm not willing to spend anymore money on that shit. so, i tried out the mic that came with guitar hero (LOL) with a USB jack and it worked fine... the problem is, i recorded the guitar using that mic infront of my fender frontman and the guitar sound was "muddy" and basically crap... so i was thinking about recording it direct from the pedal's usb outlet... would that be a good idea?
also, i know nothing about recording vocals and using compression on audacity or whatever... does anyone have any tips to help out on that?