Another good source for Vehicle Importers is the magazine "Just World Cars" which specialises in listing collectible cars for sale and available from "all good newsagents". Many list what they are prepared to do for you.
There is usually several ads there for firms offering to full services to import vehicles from the US with prices ranging from $2,500 to $3,000.... which isn't that much more than the cost of 20' container from LA to OZ.
But remember, that getting the car to OZ is the easy part... the process of getting it off the wharf, thru customs via a bonded warehouse(customs agent) and into your hot little hands will cost extra such as...
paying the Import Agent for a multitude of importation charges (e.g. Import Duty, GST, Quarantine, wharf, transportation, container cleaning, warehouse costs, and agent admin fees). Which when I did it in 2004 the cost incurred was $6,800 (which was in addition the cost of shipping the car to OZ).... so it aint a cheap exercise.
Anyway, that is the short story, the unabridged version is here
http://members.ozemail.com.au/~daniel42auWhat generation are you importing.. C3, C4, C5? Many RHD Converters specialise.
.... Good Luck...