You need to take it to a place that will check it for leaks. Usually, it's just an O-ring. What your being charged for parts AND labor seems high to me but, I guess they would charge a lot to fix a heater in Minnesota too.

I have an F-250 and the compressor and hoses were less than $300 from NAPA. I put it all on myself, then took it to a AC specialist to check it for leaks and recharge the system. That bill was less than $150.

Don't ever buy parts or have work done at the dealership unless you absolutely have to.