Congrats on the car. According to my research its really not that bad in SA. There are plenty of places you can use as parts suppliers (other than the Agents) for most of the basic stuff.
You can get brake pads and discs (ATE) at Midas.
Radiators and cooling components at Silverton.
Bruces Spares in CT; Bemows in Jhb.
And then you can DIY most of the jobs, as labour charges escalate the price of a job up to 100%.
The trick is to have your basics covered (plenty of threads on this forum going over these), do some preventative, and then regularly inspect the car and keep up-to-date. Use research to find common failure items which you need to check or replace (e.g. Fuel Pump) which could leave you stranded.