If you are thinking of purchasing the car seat outright you will more then likely find that it is non-compliant to Australian standards and cannot be fitted to Australian cars so therefore it will become redundant when you come back here. So unless you are planning on doing a lot of European travel in the next few years it may not be worth purchasing it.

Reason I say this is that we are currently encountering the same problem - we are picking our car up in Italy and our car seats from here will not fit into their cars (also for insurance purposes they will not allow it), so therefore we have to purchase car seats through the car place (they do not have a hire option) but these will not be able to be fitted to our cars back here, so we will be stuck with 2 "unusable" car seats. In our situation tho we are happy to wear this as we go to Europe every 2-3 years so they will come in handy anyway.

Hope that helps.