I hired mine from the hospital (Royal Hospital for Women in Randwick). The cost was $70 plus a refundable deposit for 6 months. I think that is the least amount of time they will hire one to you but they also are an RTA approved fitting site.

There is another baby shop in Randwick on Anzac Parade but I am sorry I can't remember it's name - they will hire you a capsule for a 3 month period.
Cheers
Ali