I also have a '91 prelude, my conrtol nob broke on the inside. I went to the local honda dealership and got a new one for $8. A used nob was going to cost me 5 bucks at a junkyard.
As for the broken tail light, junkyard is the best place. Those style tail lights aren't very cheap for some reason new. Mine has a slight crack and it was gonna cost out the *** to replace. I learned to deal with it.
As for the heat, i'd say the flap was stuck too.
It sounds like they's air in the breaks, just bleed them real real good and make sure to put more break fluid in.
I hope this helps at all!