Hey mate,
Have you tried www.dixieart.com ? I haven't ordered through them before, but it looks like they'll ship internationally.
Alternatively, contact Badger Airbrushes directly. They might be able to point you in the direction of a supplier in Australia &/or assist you directly with what you need.
Ken Badger is a pretty nice and helpful guy, he shipped me a Badger 100LG direct from their factory. Well worth a shot.
Best of luck - nothing worse than when your a/b is out of action.
Chris.