Yea, I know what it's like trying to get some things in Australia. Anyway, you'll be much better off problem-wise to try and get the original pak'ed version. I know I got mine through idstuff, give it your credit card and it unlocks the full game right there, no CD audio though. I don't know if they still offer this, however.
[edit] http://www.idsoftware.com/store/ It's actually download only now! Believe me, warez groups mangle files, you'll want to get this.[/edit]