I doubt whether QF will source these aircraft for several reasons:
they haven't made up their minds what they will buy, how many they will buy and when they will be delivered.
The 1st AC 773ER was due in May 2006. That's way too soon for QF. They were looking at receiving 773ER/346 in 2007 at some stage, but A380 EIS delays may push this out until 2008.
Boeing look likely to increase 777 production rates, so if/when QF decides to order 777s, they will still be able to get slots that suit their delivery schedule.