Volvo: A/C, car repair shop, volvo dealership

Question
I have a 2000 S70 Turbo Volvo.  I believe it is a 2.4 liter engine.  Great car.  I had a leak in the a/c, got it repaired.  The problem is that when I start the car and turn on the a/c, the a/c is great.  Driving for awhile, the a/c seems to stop blowing cold air, but it does still blow.  If I turn the a/c to off, and wiat awhile, sometimes it gets back to a cold air.  Sometimes not.  I tried opening the window for awhile, then closing the window.  I turned the a/c back on and it worked fine.  I took the car in to a foreign car repair shop.  It was a friend of a friend.  He had a tester and was going to charge me about 75 dollars to go in with the tester and re-set the computer.  He said that the computer was not acting properly.  His tester he said only went to 1999, so he tried to fix it, but did not fix it.  He did not charge me, and said that if it was fixed, to come back and pay him.  I would have done that, but the a.c still does not work.  Does this sound feasible and is the only place I can go is the Volvo Dealership?  I live in Jacksonville, Florida.  Thank you for your time and energy.

Answer
Ray,
During the time the A/C blows warm air, try and stop get out of the car and see if the compressor is in fact "engaged". There have been cases where a defective clutch on the compressor causes the A/C to not be "engaged" and also a temp sensor on the compressor that will "disengage" the compressor due to compressor temps being so high. I have seen many cars that have had the compressor temp sensor bypassed to stop this from happening. So try to see if this is your problem before going any further. Now a 2000 Y/M vehicle will need to have a Vadis or Vida based scannner system to reset any codes or to recalibrate the A/C control head's perameters. At this point the dealer might be your best choice.