By far the least expensive thing to do would be to rebuild your engine or use it as a core for a trade-in.

...aaaaaaaand I just saw that you're in Aruba.

You might want to look at 4D56 turbo diesel, they're fairly common in the Caribbean, I think, and will bolt in to your engine mounts, but it requires supporting modifications to the harness and fuel system. These trucks were pretty popular in Puerto Rico if you want a replacement gas engine.

Check out http://www.trinituner.com/v3/forums/index.php for leads on where to find replacement engines and what your options are because the Caribbean market is different from the lower 48 states.