Traveling to Australia, mostly alone, advice?

[The Legend]

I'm going to Sydney Nov. 1st, and have only booked my flight and have yet to make any other plans. My brother will be meeting me Nov. 2nd, he is flying in from China, as his work has him there for 6 months(I'm from detroit).

Anyway, He'll be there for a week, and then I'll be there by myself till the end of november.

I've read Josem's thread, but I'm gonna be there mostly by myself for a month. I'm wondering what I should do, what I should see, and where I could meet people to hang out with (hostels or what have you).

I'm pretty much limited by nothing, I'm 24, have enough cash to do some cool stuff, and am willing to rent a car and drive to wherever, or to pitch a tent and go backpacking or go biking.

Thanks