Sorry, I don't own a GPS, but the place is easy enough to find. As you come in from Pretoria side there is a Wimpy. Turn left at the Wimpy and head straight down. Road turns to the right, and the site is just a short drive up the road, on the left.
According to my map it is Waterfront street. The cemetary is marked on the map. The street is the one that runs along the northern side of the dam, the cemetary sits between the road and one of the resorts.
Maybe one of the dogs will be kind enough to go get the coords?