Air Conditioner problems of the 2006 Dodge Durango

A/c in my brand new 2006 Dodge Durango doesn't cool down properly during daytime operating hours. We live in texas and we bought our Durango in July of this year. My vehicle is equipped with dual a/c. We took it back to the dealership complaining that the conditioned air from the vents, even when the control is in the max position, is only ambient at best. I know what cold air feels like! this is texas! their response was that because of all the glass and large front windshield causes the interior to heat up and it takes a long time for the vehicle to cool down. However the a/c cools down the interior of the vehicle very rapidly in the early morning and late evening hours of the day when the sun isn't as intense.