Hey a Darwinite.
I seen this car before I left Darwin.
Try a toyota Liteace I think thay are KM36 that should have a gearbox that shoud get you out of trouble. Or further in it :P .
I sure someone in Darwin should be able to help.
Have you tried Japenese Auto mart on Winnelie road. I used to get heaps of parts of them. If they don't have it they should be able to get it.