where can i get a bilge pump from ,im in australia.

If you can find the circuit parts you can build your own using a bookshelf fountain pump...
http://www.queensown.org/technical-data-sheets-6.html

Or maybe build your own penny pump by soldering some impeller vanes and a connection rod to a penny and placing in a copper end cap and attaching a motor...

Or, if you're not handy with electronics, you could go this route: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDZ48
These Ram pumps are available internationally from what I've been told. It's small enough that shipping prices shouldn't be prohibitive from the U.S. or Europe if they're not available in Oz.