Dude, only seen this post now. Don't know if you still on the way, or come and gone already??? You can get all major brand components here - mostly in LBS. However, you are going to pay 10%-30% more here than in the US or EU. I can give you LBS details, but it depends which city you're going to be in?
Enjoy your trip! We got some awesome riding here....!
Try
http://www.sportsdirect.co.za for an idea of prices