Air Conditioner problems of the 2007 Dodge Nitro

Brought truck to the dealer due to air conditioner (a?c) not cooling off the truck. They stated they tested and it was working normally. After picking up the truck on / 7/19/07 went home with ac on, it was 84 degrees outside. Put the thermometer in truck and drove with windows up and a/c on high for 1 hour. Temperature outside was still 84 degrees, but temperature inside truck was 80 degrees. Drove back to dealer service department, left truck running, showed them, and they told me that it was normal, because the cold air at the vent was 45 degrees, but at the driver's seat it was 80 degrees. This has to be a problem.