You will need to get it re-gassed, if there is a problem with that like a leak then they will highlight that fact. After re-gassing and the AC still dosent work then either the pump or the conderser has gone down. The garage that does the re-gassing might be able to tell you what the problem is by looking at it or it could be down to the car needing re-gassing. AC systems should be re-gassed once a yesr.
Kind Regards
Tristan Hanwell, July 2006