97 Camaro V6 A/C

The a/c in my v6 camaro has been blowing hot air for the past few weeks. I had refridgerant put in it. But the line from my compressor going into the interior of my car would freeze over and my temperature gauge would slowly rise, causing the engine to overheat. Once I shut off the a/c, my temp. Would go back down to normal running temp and the line would defrost. What should I do to fix my problem?