The price they have quoted is way out of line. We sent a letter of tender to 31 Volvo dealerships last year for our a/c rebuild, and the highest was $1300. We eventually paid $875 for everything after some negotiating. Here is what that replaced: 

Replace A/C Condenser
Replace O Rings
Replace Receiver dryer/purifier/accumulator
Flush Compressor/System hoses (system has been vacant for 3 years)
Replace Compressor Oil
Evacuate System
Clean evaporator drain
Recharge with R134a refrigerant
Dye Test for leaks
Filter Screen

I suspect they saw a brick and assumed you were loaded, and uninformed about your car. I would suggest paying an estimate fee from a repected Volvo dealer to get the straight goods, and perhaps another estimate elsewhere. Then, with the two estimates, go to the shop you want to do the work. Goood luck!