Where in Aus are you?
Here in Melbourne, I just went to Bikemart, told them I need new chain and sprockets for an NSR MC21 and they did the searching. At teh end of last year I got:
DID X-ring chain $95 (on sale)
cheap generic front sprocket $25
cheap generic rear sprocket $44
Having read some more into chains and sprockets ("the chain gang", an aussie sprocket manufacturer, was referred to)I think next time I will go with good brand everything. It is supposed to give you better longevity.