Get yourself an LG PB63U LED Projector with Wi-Fi for $499
Here is an LG Electronics PB63U LED Projector that you can buy from Amazon and save $50 in the process. This is as cheap as you can get. It ships directly from Amazon to Australia and the shipping cost is only $25. This project comes with Wi-Fi so you should be able to connect it without having to use any cable. Keep in mind that the adapter that it comes with is the US type so you will need a converter to be able to plug it in an Australian socket. Also the TV tuner won't work in Australia but of course your PC will work just find.