Don't know what the exchange rate and availability is for items from "up here" for you folks "down under" but here is a reference to the standard O2 sensors that are compatible with Ford's system using the A9L EEC.
http://www.fordfuelinjection.com/?p=89
Specifically:
Heated Oxygen Sensor (HEGO) 8″ pigtail Ford E9SF-9F472-AA
Standard Motor Products SG23
Ford Motorcraft DY605
Bosch 13942
These are all 3 wire O2's and up here, at least, they range in price from $25 to $60 US.
DonC