Find out about the AA program - if you fly on BA in World Traveller Plus once a year, and do some flying in Australia on QF, you may be able to earn enough miles in AA, using a Platinum (equivalent to QF Gold) Challenge, to get to Platinum level.
AA Platinum will entitle you to "mid tier" benefits, which in the OneWorld alliance is "Sapphire". Importantly, this includes lounge access in OneWorld lounges, except for AA lounges when travelling domestically in USA.
Have a good search in the AA forum for more information about this.