If you can get to Makro in Woodmead, (M1 North going from Grayston and taking the Woodmead offramp), should give you some decent choices.
Also, look up Liquor City - they are starting to stock more craft beers, CBC is a popular one.
Otherwise, try Norman Goodfellows:
https://www.ngf.co.za/beer/beers/craftbeers.html
They have a branch at Benmore Gardens which is at the corner of Grayston Drive and Benmore Road in Sandton. Parking is an issue though.