Volvo Repair: A/C not blowing cold air, th model, evaporator

Question
I've had the ac recharged twice this summer. The last time lasted 20-30 days.  This time I noticed that under the car's engine on the driver’s side was a fresh leak. It was oily and very clear and w/in 2 days the ac stopped blowing cold air. When driving you can hear the compressor turn on then cycle off and on and off etc. I have turned it off completely. I went to the gyear location and explained my problem. With out looking at the car they told me it was my evaporator and would cost $1,700+ taxes. I was shocked that he knew what it was w/out actually looking at the car. I am reluctant to believe this off the cuff diagnostic. Maybe I'm wrong and he's right. I you could help I would be appreciative. Can I repair this on my own or will I need to have it professionally worked on?

Answer
Wayne, If you told me th model of your car I could confirm or deny it but by the sound of the price its gotta be a 850 or S70.  His estimate is way high.  It should only be $950-1000 range.  The dealer is cheaper than that. I wouldnt take my lawnmower to goodyear.  Find a reputable Volvo shop and have them check the car out.  Roger