F/A22 is all you need
Although a fleet air arm would be great for prestige, we simply don't have a navy large enough to support a carrier. A carrier on it's own is a sitting duck, Consider our nearest potential threat has ordered Kilo class subs as well as Korean type 209s with vastly superior lethality.
In the air our fleet air arm we will be facing Sukoi and MiG 4th generation fighters that from all reports have far more energy (energy = life) than our 18's. JSF is only marginally superior and it was designed as an F-16 (3rd generation) replacement.
We need the Raptor and we need it now. You can scour the web for the 10-15 F15's vs raptor scenarios, in two words air dominance.
The US will give us raptors, it is a vastly superior platform that can cover distances the size of Australia.
Considering you need conventional JSF's, STOVL JSFs AND a fleet air arm this is beyond economics.
Raptors will keep the air firmly on Australia's side so Helo's and other tactical aircraft can operate without heavy losses.
You need to counter a 4th generation fighter threat with fifth generation dominance not a stop gap. JSF vs SU30's and MiG 25's would be marginal, considering our adversaries ability to field larger numbers we would not be able to secure air superiority which from every lesson in every war is vital.
Without the air our MBTs would be vulnerable as would our troops and our seaborne operations. We'd need vast amounts of extra resources to try and defend. If we concentrate our efforts on a carrier group imagine what the devastation would be if we lost her. There is no doubt in my mind that enemy would make that the first task on the to do list.
we need the Raptor and we need it now