English Schools for Foreigners in Jo'burg? (TOEFL) (Johannesburg)

Hello,
I'm looking for an English school for foreigners in Jo'burg, better if in Sandton.
I need it in order to proceed to get subscription for TOEFL certificate.
Please, if anybody knows a good school, could indicated here? It would be probably a good information for everyone of us have not English as mother tongue.

Thanks a lot!!!

Ciaooooooooo!!!

Emilio