$400 for 12 bottles of wine? That's $33 per bottle and if you have to fly any domestic routes with it perhaps huge excess luggage fees.
I too will be in South Africa in May spending several days in the wine country near Cape Town. I may have some shipped.
Look at
http://www.ewine.co.za/shippingWorld...imageField.y=8 to get a feel for shipping costs. It suggests around $303 for 12 bottles including packing and insurance.
I am sure most vineyards offer shipping. I have seen other pricing at about $13 per bottle.
Many South African wines are sold here now. We are buying several to taste so that we will know whether it is worth the effort and cost of importing. Suspect that the local US selections will grow rapidly as SA wines are growing in popularity here.
You might want to seek info in the African forum.