I'm assuming you have good air flow coming out the vents in the dash? If so, it sounds like your AC is working normally, but you aren't getting airflow thru the condensor at idle. The condensor looks like a thin radiator that's usually placed in front of the engine radiator. There needs to be good airflow thru that condensor to dissipate heat just like the engine radiator needs it. Basically, the AC system takes heat from the cabin of the car and dumps it off at the condensor. If there is no airflow thru the condensor to carry that heat away, then it just goes right back into the cabin. So if there is little or no air being drawn thru there, you will need to find out why. If that's the case let us know.

If you simply have very little airflow out the vents in the dash, then you need a new blower motor. (At higher speeds air will be forced into the car thru the vents)