Well first thing you get in contact with AASA:
http://australianautosportalliance.com/aasa/
Every person competing will need a AASA Club License ($50) or a CAMS L2.
You will need to organise and pay for a clerk of the course maybe marshalls or something.
You will need to organise a AASA permit and maybe insurance.
Given that you don't know about racing licenses, why do you want to do a timed event?
Have you gone into AHG/RAC to discuss this with them? Or just called over the phone/email? I'd suggest going in to see them and discuss what you want to organise and the best way to sort out organising it. I'm sure they get a lot of time wasting calls on this sort of stuff.