I'd go and take a look at that 535. Or maybe look for another 5-series. I can't recommend specifics because I don't know how to calculate running costs for an australian car. I have no idea how taxes are, are they fixed or based upon engine size or what ? The same for insurance.
Don't stare yourself blind on the initial cost of the car. But do make sure that you get the running costs calculated correctly and that you're sure you can pay for them. Initial purchase is nothinh compared to running costs as you have probably learned by now.
I wouldn't get anything with an auto box. Autos are..meh.