My strategy would be to convert the Citi Prestige points to Avios (the current 300K sign-up bonus would be enough for Australia to Europe one way in QSuites) then acquire Velocity or Singapore points to book a Singapore (with Velocity or Singapore) or Etihad (with Velocity) flight in the other direction. There are lots of credit card programs that transfer to Velocity and Singapore:
The Ultimate Australian Credit Card Points Transfer Matrix
You could also consider buying Avios points if you only want to fly Qatar, but that is more expensive than credit card churning.
Edit: Reading the
OzBargain thread on the current Citi Prestige deal, it looks like you can churn Citi Rewards program cards on a very regular basis (eg every 3 months, if not more frequently). So I'd also consider getting the Prestige every time it has a sign-up deal.