I recommend O'Neill, he has been doing it for awhile and gives you questions that have been on previous papers before. I had a couple of friends who did the GURU prep last year and are doing O'Neill this year and have said that O'Neill is the better of the two.
O'Neil does courses in Melbourne you just have to book.
You can start with the Gold Standard textbook or DVDs. They cover all the science subjects in details. You can also get enough practice from them.
The author Dr Ferdinand is going to give seminars in the University of Sydney and UNSW. He is planning to go to MU next week somehow.
Hopefully you will enjoy the products and the lectures.