Air Conditioning

I bought a brand new 2007 Honda Civic LX two months ago and now that it is over 100 degrees outside I have realized the air conditioning system takes a while to start cooling. I have had a number of cars and have never had a car take this long. I called the dealer and they said it would be $150 just to diagnosis it and unless they find a problem I have to pay out of pocket. I was told they do have to do this from time to time or the system will over cool but there is no way it should be over cooling when it isn't even blowing really cold air. I feel the system must have some problem because it blows hot air out when stopped and unless you get to a high speed with no stops for a few minutes it won't cool down. When running errands around town it takes at lease five minutes to start cooling down dramically and if you stop it goes back to barely cool until the whole car is cold. It works great once the car is going a while and the car is cool, its just when it gets started. If this is just how the car runs I find it unacceptable and I wish I knew this before purchasing it. Do you think there is a problem or just me wishing it would work better?