Hi there Alvin, first welcome to SAU.
Now about your question. Ive decided it would be better just to give you a few web links rather than give u a direct answer myself. Reason being is im not 100% positive.
This website is VicRoads. They are Victoria's road and traffic authority and deal with car registrations and the buying and selling of a vehicle.
http://www.vicroads.vic.gov.au/Home/
Introduction to Registration
http://www.vicroads.vic.gov.au/Home/Registration/
Buying and Selling
http://www.vicroads.vic.gov.au/Home/Regist.../BuyingSelling/
Also the fuel prices in Victoria at the moment vary between $1.05 to $1:38. This all depends on the area you choose to fill up, the kind of fuel you are going to be using (92oct, 95oct, 98oct, etc) and also the time when you fill up. For me its generally cheaper on Tuesdays than any other times of the week.
Well i hope ive helped in any way. If anyone else has any suggestions or answers plz speak up as i do not know alot myself.