Taz,

R12 is Freon, that is not be available in Canada (no longer legal here) but the kit to retrofit the old a/c system to the new refrigerant (r134) is available (I got it from my volvo dealer last year) , it shouldn't cost much more than $150 for the parts from the dealer and a couple of hours of labour. If All the shop is doing is converting to the new refrigerant than $700 is WAT too high. I got the conversion kit, had it installed, and wound up replacing the condesor when they rechagerd (and if I remember correctly had a pressure line replaced) for about $800 c at the Volvo dealership. I would get a second opinion (if the quote wasn't from a dealer, try it see if their price is similar, otherwise try a different local AC specialist (NOT canadian tire, they don't know what they are doing!).