As you're working outside Oz, I presume you are earning foreign currency. You would have to buy A$ before you transfer. To get more A$, you have to buy it cheap, like NOW (about parity with the US at least).
There's a limit of A$10,000 when you bring it into Oz and if you declared more, the authorities are going to ask you lots of questions. If you are declaring anyway, why don't you let your bank do it for you ? Conduct an electronic funds transfer if you've got internet banking. Some banks do a very good deal and no fees are charged for such a transfer (all managed from your computer at home).
Don't forget if you are Oz resident, you'd still have to declare this income.