I'd have to agree with the others on this thread - if you purchased the car from a dealer and it was advertised and represented as something it is not, they might be subject to action under whatever State laws apply for false advertising. However, as you purchased the car and apparently were satisifed with the transaction, it may also be that you are buggered and will just have to llive with the car as it is without redress.
If you are a member of a motoring organisation such as the NRMA, they have a legal section which provides advice free of charge to members on motoring laws etc. Might be worth giving them a go.