Lou, you should be able to get the lens for around $188. If you buy a parallel import lens, make sure it comes with an international warranty slip (get the seller to confirm). Canon and Nikkor lenses have international warranties - means you can get it fixed in Australia.
I've bought lenses and speedlights (covered by international warranty) from this guy:
Discount Digital Photographics: Accessories for Nikon Digital SLRs
For camera bodies (covered by national warranty) I've had both David Jones and JB Hi-Fi price match D-D's price.