Major air conditioning problems - help!

My 2006 Prius started having air conditioning problems at 48K miles, post warranty. Dealership said freon level was low but no leak was found. At 55K, I was back at the Dealer's service department where they found a small leak and repaired it. Freon full again. Winter came. At about 65K I was back again due to A/C use for lack of cooling. Dealership said the condensing unit failed. Replaced condensing unit for about $800. At about 68K it was not cooling again. Was told condensing unit was full of debris, cleaned it and that seemed to help, a little bit. At about 70K I was back with no cooling. Was told it was the condenser by two dealerships (with hugely varying qoutes to fix it, but both in agreement about the problem), so had condenser replaced for $1,600. A week later, A/C was not cooling. Dealership said it was a valve failure; had leaked freon so replaced valve and added freon again The next day it was not cooling again. Dealership says there is a leak in the condenser coil located within the dashboard and it will cost $1,400 in labor alone to fit it, plus $440 for the part. I have no confidence in the dealer or in the car's air conditioning at this point. Dealer says he will try to get Toyota to pay for the part and he will reduce the labor cost to $1,000 but really? Has anyone had so many problems with the air conditiong out there?