Pontiac Repair: 95 bonneville A/C problems, pontiac bonneville, cooling coil

Question
I own a 95 Pontiac Bonneville that has been going through stages of A/C problems.  At the end of last month I had the condensor replaced (took it in to have it recharged and found that it leaked.) Less than a month later I  started the A/C after having the vehicle sit for 2 weeks and it only blew hot air.  Took the car back to the same shop and they stated this time it was the cooling coil behind the fan under the dash and quoted me another few hundred dollars for the repair.  I understand the basics of car maintenance and parts, but I am far from an expert.  I feel I am getting ripped off since the car was in the shop less than a month ago and I feel this should have been caught the first time.  I have not had this second repair done yet.  What, in your opinion, would be a general repair cost for this relacement of the "cooling coil." Is this a repair that a relative with general car repair ability could do for me or should i "let the experts" handle it since it includes going through the dashboard? should I take it elsewhere than this first shop? I am sick of all these repairs on the same sytem and all the $ I am putting into an older car that runs great except that I am cooking in my seat on my way to and from work! any help would be appreciated! forgive my generic lamen's terms!

Answer
The condensor and the evaporator  core are the two problem areas in the AC system on your car. Weather or not they found the second leak the first time doesn't matter, it is still leaking. I would say that the average labor to replace the evaporator core is around $500. Not really to sure about the price of the part.
It does not come out through the dash, it comes out from under the hood. I dont know your relatives skill level but it is not really a hard job to do. You will still need to take it to a shop to have it charged up after the part is replaced.
If your relative wants to try to do it, and runs into any problems, just let me know and I can help walk him through it.