Hi Shelley,
I flew to Melbourne 2 months ago and stayed there for a month 2 weeks in cbd then 2 weeks in St Kida, Melbourne is a really cool city, $3000 will be more than enough for a month or so, just be careful with your money as its easy to spend it fast!! I'm having to work a lot sooner than I planned! I'm now in Perth I drove here with someone I met in a hostel in Melbourne, theres loads of work here in Perth, I'm now going to save up in winter then do my farm work and travel the east coast in the summer as Britpop said theres tonnes of house shares on Gumtree they sometimes work out cheaper than a hostel... but hostels are a great way of meeting people and making friends, not long until your trip begins hope you enjoy it sure you will!!