Found the flange at a Napa store nearby, but they have to order it from Columbus, OH for 15$. Not too bad I guess.
I think I might just cut the rusted portions out of my current one, use that new flange, put a glasspak where the muffler is rusted out, and drive it to a muffler shop if I can find one.
As long as the exhaust pipe has that glasspack on it and is about 3-4 ft long, I shouldn't have to worry about cold air backfiring and warping my valves, right? Just for long enough to drive it to a muffler shop?