Well, you were not very specific and rather confusing in your post. The condensor has no bearings in it, it is what is infront of your radiator and acts similar to a radiator except it pulls in heat instead of dispersing it. That only needs to be replaced if it has a hole in it. Your AC blowing hot air could be due to the compressor not turning on which could be because of several different reasons; no refregerant charge, shot compressor, bad switch. Also, it depends on which bearings the mechanic is talking about being bad, if it is within the compressor then yes, the whole thing should be replaced if just within the clutch then no. Hope some of this helped. Also, I just finished restoring my AC system don't be afraid to do it yourself it is really simple and you will save yourself $.
Doug