throttle position sensors

Also what other transmission or gearbox can fit into this vehicle ? or rather a combination of engine and transmission?

update ..was driving today and my gears would not go in ..automatic transmission..all the fluid was out ...when checked the fluid line from the radiator was torn ..had to replace it when we checked it seems that there are leaks all over the place for example the shaft has fluid meaning thata it could be the axle leaking?
more research has to be done ...would keep the post updated

I'm afraid we don't have much experience of auto transmission on the forum, they are quite rare over here, and they tend to work until they fail completely, and are then too expensive to fix, as you are finding out.

TBH, I'd put my money into a replacement vehicle that can be easily repaired locally rather than keep throwing it at a 10 year old one that seems to be developing more faults all the time, but it is your choice after all.

Good luck with it if you decide to keep it