Beginner Interface Options

[mancabbage]

Yo i have a 1.25 gHz imac with 256 ddr sdram - ive been recording using the iMic to plug in my gutar and my mates digital drum kit for a while now but the quality is just terrible to be honest - whats the next step up - i know i need an interface to plug stuff into the computer but i can cope with only one input as we have no intention to record our stuff all at once - we all guna do our bits over the drum track one at a time - im on a budget and have noidea where to look - any help??