Qantas has already ordered some A380s, but they know that the only way to acheve the per seat savings Airbus promises is to fill the plane on every trip. With such a huge plane, they will lose money fast if they have to fly half empty.
They have to buy smaller, more fuel efficient planes for many of the other runs that don't sell out, and they want longer range planes to open up new direct flights.
That means either the Dreamliner or the A350 for the former, and either the 777-200LR or (?) for the latter. It may also mean more 747 Advanced and fewer exercised options for the A380, since the 747 Advanced can use airports that haven't upgraded to handle the A380.