I'm with Gareth, I would certainly say your a4 has air con Brad :)
May just need a regard or air con service. Regis should cost approx £30 and a full service should cost around £60. the worst case scenario for the air con not working is a failed pump/condenser. This is the problem with my a6 but iv been quoted approx £1000 to fix the system!
In my case i know the air on doesn't work as the car puts econ on automatically and even when turned off it comes back on.
Cheers
steve