Hi Angel - I don't know of any specific teachers in your area but quite a few people from there have asked the question so perhaps there is a teacher or reader out there that can let us know? Alternatively you can try the websites of the South African Iyengar teachers or the Remedial Yoga teachers. Prices generally vary considerably and range from R 20 to R 80 per class. Many people "graduate" from doing yoga at gyms and prefer to deepen their practise in a more focussed environment, although some teachers at the gyms are great.
Regards
Chris