Brisbane is 922km (10h 39m) from Sydney and even further (1,788km 19h 46m) from Melbourne. Don't even think of driving from Perth - we recommend flying. This page has plenty of flights to Brisbane. However, Virgin Australia often run deals that are only available on their site and don't forget that Flight Centre will match any advertised fare.
You probably already have an idea about what you want to do when you stay in Brisbane. One thing you definitely, absolutely must add to your list is a visit to the Gallery of Modern Art. GOMA, as it is affectionately called, is possibly the best modern art musuem in Australia. The displays change frequently and there is also a dedicated kids section, so you can bring them along. Top it off with a great location in the centre of Brisbane.
Brisbane is 922km (10h 39m) from Sydney and even further (1,788km 19h 46m) from Melbourne. Don't even think of driving from Perth. For that reason, we recommend flying. For cheap flights, try IWantThatFlight.com.au as they specialise in finding cheap domestic flights.
From the airport to your B&B, why not go in style? Uber are a great alternative to taxis.