Go to http://www.saclimb.co.za/northern/wellington_main.html
Wellington dome is quite cool, it offers very frictiony slab climbing, there are some pretty nifty multipitch routes there. That will be your closest sport route to Botswana.
If you want to climb trad then you have blouberg but then you need to budget anywhere between 4hours to 9 hours on the hike in. (Depending on how lost you get). The climbs can be as long as 20 pitches, so they obvisoly require quick efficient climbing, unless you want to bivy.
I reckon try out wellingtons dome, if you have a tent, there is a farmer nearby called jaap moller who allows you to camp in he's premises.
Hope this helps