Have a look through the for sale forum on here, there's a few different breeders around the Brisbane area - Baden (Solar17) has some great quality rats at a decent price
Livefoods unlimited at tallebudgera valley, Rodent farm is stocked at city farmers stores (and possibly others but I know city farmers has them), there is solar17, david evans and brent on here that sell rodents in brissie. all three breeders are northside. sent you a pm with links
I buy my stuff from Baden and I can give nothing but positive feedback. He has been readily contactable, easy to work with, provides good quality rats and has decent pricing.