Ramsey, Warn and Superwinch all have dealers in South Africa. Contact information is on their websites, at least for Ramsey and Warn. 'winch name'.com
I would contact these dealers and ask their advice regarding shipping.
You'll need a mounting system for the winch, a fairlead and also check that the winch comes with proper battery leads. If there are no trees or large rocks in the area, you'll need to create an anchor.
Understand the limits of the winches, otherwise you could disable your vehicle worse than just being stuck.