Might want to find a diagram of the brake system and see if you can devise some additional tests. Seems to me like sticking front brakes are unlikely to be a master cylinder problem. More likely deteriorating brake hose inner linings or a sticky caliper (or maybe the proportioning valve?).
The 12 and 55 codes are just brackets saying first code and last code respectively. The other codes are:
- 32 for gas engine chrysler products is usually no EGR. Do deisel's even have Exhaust Gas Recycle?
- 37 is some sort of unhappiness with the transmission.
A readout of the actual OBD-2 codes with a real codes reader will get you more details.
A quick Internet search says you can probably find rotors for way under $400 each. The cheapest ones are probably junk, but they are probably better than what is on there and even in roadsalt country, they may well outlast a 13 year old vehicle.