Welcome to the forum
With QF upgrades are only by
(a) pay the fare difference in cash. QF are not known to discount the cost at the gate-you pay full $$$
(b) Using QF points, but this is a lottery with the winners (if any) advised few hours before the flight
SYD-LAX is a very popular route for upgrade and J & F awards.
With QF always expect to fly the class you pay for
Why are you a member of AAdvantage and Lanpass?