On a tight budget I'd go with canon as nikons have a bit of a premium in SA and there are a helluva lot more 2nd hand canon lenses/accessories floating around.
really if you wait and watch Nikon, Canon, Pentax or Sony will be available with your price range ... the trick is research what brand you like and why ie lense type, features, handling, technological pace, update etcs.
You can pick up a cheap Sony A230/A280/A290 and they OK, but you will have low light issues and Sony seems to update their range every other week so you behind before you begin.
Pentax is pretty rare in SA and while they excellent cameras you will pay.
Nikon and Canon are of a similar ilk, reliable, tested and crud of o stuff from lenses to odd fiddly bits you never cared about until you see it.
Look maybe at the Nikon D5000, I know you can pick up a D3000 for about R3000. D3000 is a good camera, and an excellent starter camera equivalent to the Canon 1000D.
If you want in there is a way, and the first bit is a simple camera that will help you realise what you want from a DSLR and then I would worry about bigger, better, more.