1998 Plymouth Voyager A/C?

We bought this van and was told the switch for the A/C & heater was broken, so each season you have to take it in to have a mechanic change it over to either A/C or heat. It blew A/C out the drivers side, and heater out the penger side. We took it to a mechanic who "opened" the penger side more so it blew A/C (but still warm). We wanted to permanently fix the problem, and took it to a mechanic today who said we need to buy a new heat & A/C module for it to work. When we called him he said on the phone he knew what the problem was already & would charge $200, after he looked at it, the part will now cost $450 with $55 for labor. He's also supposed to be a body shop, so we had him look at the plastic bummper in front which was hanging, he wired it up to the frame of the van to "fix" it. Then our penger side mirror was loose & he super glued it back in place. The other shop we took it too said it would cost $3-650 to fix the A/C & would have to pull the dash. This guy...