Well, with a 3.7L things are pretty easy, straightforward, and more cost effective than getting a replacement engine.
You can find some 2004-2005 5300 vortec engines for pretty cheap. I think that will be a drop-in conversion. The oil pan will need to be changed (or a lift kit to clear the axles) but that is about it. Your current computer might be able to run it. Otherwise, a vortec computer is not that expensive. You will need some custom wiring,exhaust, and intake work but that is pretty easy considering that it is a GM. You can also use the Alpha ones with little modification. You will be able to retain all H3 functions (example: ABS, traction control, Cruse control, Air Bag ... etc).
I'm "guesstimating" the swap cost will be less than AED20,000.
Try to contact Cobra workshop in Dubai. Those guys are the GM conversion experts. They do lots of 5.3 to 6.0 conversions. So they might also be able to provide you with a cheap 5.3 vortec engine.
They are also experts in Custom GM wiring. So, They can give you a good advice about This v8 swap.
Good luck and keep us updated !!