Help with brakes?

[jdw]

I've got a 1972 c10 and developed air in the lines. Fortunately, the drums started smoking at a brake shop. Yeah, right. The shop replaced a couple of the lines that had rotted out, the master cylinder, and bled the heck out of them over the course of 3 days. Unfortunately, the brakes now function like coaster brakes. The pedal feels pretty firm, not soft and squishy. However, it goes almost all the way down and the truck just sort of rolls to stop. The shop owner was pretty cool and since he couldn't fix the problem didn't charge me for anything more than his cost on the master. I could only maybe understand about %40 of what he was saying and since I only originally went there for exhaust work I drove the truck back home. 350 horse with coaster brakes behind a cop scares the hell out of me.
Other than the basic mechanics, I don't know the first thing about brakes, I admit that. Before I start hemorrhaging cash I don't have, any suggestions on where to start? Slave cylinders? Booster? More bleeding? Since the shop I was at couldn't fix it (it's predominantly an exhaust place, and that work was excellent), I'd at least like to get some suggestions even if I have to take it into my preferred mechanic if I can't do it myself.
Thanks, guys.