Schooling in Australia can be very expensive. A private school can cost up to AUD 25,000 per year. Faith-based schools can be a fraction of the cost at about AUD 2000 per year, but obviously that is dependent on the area and the quality of the school.
Please have a look at our page on Education and Schools in Australia as this will give you more detailed information as well as some information about temporary residents on a 457 visa.
Also see Cost of Living in Australia for more information on the cost of education in the country.
The best of luck with your move to Brisbane.