With the last two months I have had all of the above mentioned items replaced by the dealer. The spring seat is definitely a dealer or alignment shop repair unless you have a spring compressor and the necessary tools like that to repair and then realign your front end.
The a/c light is from the blower motor short circuting. Usually there is another circut with that that will go out. The parts are about 250 to 300 and labor about 1.5 hours. This is something that I was able to wait on about 9 months before repairing.
The timing belt is something that you local VOLVO independent mechanic can do. If not, try to see if you can get the dealer to give you a package price on all of these repairs or a AAA discount. The belt repair shouldn't be more than $250. The standard price on the belt from the factory is 55 bucks. Labor is about 1.5 to 2 hours.
So in total for all your repairs you shouldn't pay more than :
Timing Belt : 250
A/C : 450
spring seat : 130 per side.

Hope this help. Oh, if you want to save yourself some money, and you only want OEM parts on your car, buy the parts ahead of time from Volvo of Houston and you can save a bunch. They will sell you the parts for about 30% less than the standard dealer. Then bring the parts with you and tell the service advisor that you have the parts. You will save time and money.