Buying a car - Need it only four months

Hi all, from January till May I will visit Australia for the second time. This time I have planned to do the circle Melbourne - Perth - Broome - Darwin - Melbourne. Since I am quite adventerous and doesn't like to sit in a bus, I am planning on buying a car again.

The difficulty is that I also have to sell it at the end and if you are not able to sell it in lets say two weeks, you lose all the money you invested in the car. So I am thinking about what to do and would like to ask you for advise about this.

Do you think there will be carsellers who will sell me a car and make an agreement that they buy it back after four months? I understand they couldn't garantie me a price, because it all depends at the state I will return it in.

A 4wd will be nice, but I am not technically skilled and an if an 4wd breaks down, it is probably going to be more expensive than for example a Falcon or Commodore, am I right?

A Falcon or Commodore has my preference, for these reasons:
1. In The Netherlands the fuel is twice as expenive as in Australia, the roads are narrower and there are almost no cars with 4 or 5 liter engines. I would like to drive such a car for a while.
2. They are common cars in Australia and if they break down, it will be easier to get parts.
3. Bigger car carries more stuff and is more comfortable to drive in.

Otherwise I was thinking about a Toyota, since they have proved to be the most reliable cars there are.

My budget for a car will be around 3000 A$ or a bit more if I have some sort of garantie I can sell it at the end.

It is a long story, but I am open to any advice anyone can give to me in this matter!!

Thanks in advance.