Air Conditioner problems of the 2004 Suzuki Forenza

I bought a brand new 2004 Suzuki Forenza from a Suzuki dealer in tucson arizona on 05/21/04. From the first day we did not feel that a/c was working correctly and was cooling after a approx 30 min drive. I bought a temp gauge to check the vent temp and the reading will not go lower then 50f. All driver's should know that a nice cold a/c should reach 40f at its best performance. We took the car to the dealer and was told that the freon was low and have corrected the problem. The a/c worked good for a couple of days and started performing the same as before. Second time, I took the dealer technician with his digital temp reader on a drive. The outside temp was 106f and the vent temp was 48f. Please note when I went to the dealership the car was running for more then 30 mins. Dealership referred to the Suzuki tech line and told me that there is nothing wrong with the a/c. There explanation was that if the outside temperature is 99f then the vent temp should be higher then 50f and as it was 106f outside, your a/c is working fine. The dealer will not repair or replace a shoddy, cheap air conditioning system. Please check all items on the car prior to buying a Suzuki automobile.