Take a DSLR with a 300mm lens and binoculars. Don't forget a notepad as you will forget a lot of the things you see and hear and your notes will entertain you for years to come. Try get 2 field guides for mammals and birds of southern Africa, this will add immensely to your experience.
If you have some tine for touring, your options are endless. A few days in Krueger NP would be excellent; also Ithala and Hluhluwe NPs, St Lucia Wetlands, Swaziland and Cape Town. My wife loved a birthday gift of a few days at The Elephant Sanctuary near the Magaliesberg Mountains on one of our trips and if you're on the southern coastline around Hermanus and Port Elizabeth you can check out the seals and penguins, go whale watching or horse riding along the beach.
Too much to do, you're spoilt for choice. Start with a map and maybe pick up a Lonely Planet Guide if you don't know anything about the country. You'll love it.