As I was trying to take out the left rear bleeder screw, it would not unscrew at all.. In fact,t he wrench rounded it off before it budged, so I banged a smaller socket over it and removed it.. Anyways, the new one will not go in past a few turns, and since I have had horrible, horrible stopping power since, I was wondering if it was ok to retap the hole? (No fluid leaks from it the way it is, but it doesn't seem to be working that great).. Is that ok to do if I really blow the metal bits out of there after?

What you need is called a bleeder repair kit. Simply follow the directions for drilling and tapping with the kit.

Yup,
What he said, easy fix, and make sure you get the shavings out, a couple of rare earth magnets are good for that. If you run into that problem again, a little heat from a propane torch and a flare nut wrench go a long long ways.

Well, tried tapping, now she won't close.. Guess it's time for that new caliper..