How much will I need to travel Australia for 6 weeks?

thanks xx

About 7,000 Aussie bucks should give you decent passage unless you're fortunate enough to meet an Aussie who hasn't got short arms and deep pockets.

Airline ticket from the Americas is $2 000 alone - backpacking is cheap - everything else is expensive

Fares to Australia to America were 1700$ AU but in the last couple months have dropped markedly to just under $1000AU (I assume this would be the case if you are going the other way as well)
Depend how you plan to live as to how much money you will need The current exchange rate is ~1$AU is about 0.83cUS
When I travel around Australia I tend to stay in backpackers most have private rooms for 1/2 to 2/3 the cost of motel, the Hyde park in Sydney is one of the better ones http://www.yhotel.com.au/ and it's right in the city.