Thats no Moon, Thats a space station!
As far as i am aware the only filter we have is the pollen filter under the scuttle panel in the engine bay and they are cheap as chips to replace.
Otherwise you may need to get your aircon regassed/serviced as this can make a marked improvment to both how cold it blows but also smells in the car as they can get a bit smelly. Had mine done earlier this year for about £50 and it now blows nice and cold and has no smell either.
Audi S3 8L BAM 225 2002 - Ming Blue : Silver Heated Leather, Armrest, RNS-E & Bose, Alloy Mirrors, Gunmetal 18" RSTT`s, Sunroof, Cruise, AutoDim Mirror & usual S3 extras.
Mods : Revo Stg 2 & Select+, FMIC, 3" DP & 200 Cell Cat, 007P (New Piston), Jetex Filter & 80mm TIP & Heatshield, LED Sides & Fogs, Gen VW Aero Wipers, Full Powerflex Kit, Lowered on AP Shocks & Springs, 15mm Front & 20mm Rear Spacers, N249 Delete & Catch Can, AP TVR 4Pot Brakes & DS2500`s, Sachs DMF & Carbon/Kevlar Clutch