Well, the AMP is located under the glove box (take off the cover above passenger foot area, and you should be able to find it there along with the ECM). I think the easiest fix in your case would be to just buy one of these amps second-hand on eBay for like $30-40 and replace it. EDIT:
here's one for $35
Otherwise, I'm not sure if bypassing the amp would work very well, as the non-amp audio systems (like mine) don't have the tweeters in front doors, so you might end-up with your tweeters being not used.
If you do want to proceed with your original plan, just locate the amp, and from there on you gotta make sure you figure out what cables go where.
Hope this helps.