With use of a VPN you can create a Amazon Indian account and then signup for your Audible account,With Amazon India you can add your Australian Bank Card/Credit card and Australian Billing address and still access Audible service.
Audible India can be subscribed for just Rs 199 per month($4-$4.5 Varied due to exchange rates)
Audible Australia offers one membership option for $16.45 per month
Hope this helps someone who uses this service.
Personally i just logged in and activated 1 month Free service to test it before deciding whether to continue or not.
So to all who wants to try here you go 1 month free membership of Audible. :P