There are a number of services that allow redirect USA products from a USA shipping address to Australia.
http://www.priceusa.com.au/ is pretty good.
They work differently to the others. They actually buy the item, and you pay priceusa for the item + shipping to Australia.
For most of the other redirecting services, you buy the item in the USA and ship to the services USA address. You then pay a a price for the item to be shipped from the USA receiving address to Australia.
I have only redirected from the US a handful of times, so I do not have experience of most of the services.
All I can say is that the Singapore Post-run VPOST is pretty bad. You eventually get the item, but their website is incompetent and they have no idea where the parcels are, in spite of their tracking. I have used them about 3 times, and I have probably spent a total of 4 hours on the phone to Singapore trying to work out what is going on.