It is indeed 2L of wine per person. I brought in 4 bottles (2 for each me and my wife, which is really only 3 litres but I only had a four pack shipper in my bag.
We supplemented that with a few bottles from Relish Gourmet (Nanny Cay location is across Omars from the RiteWay, next to the Scuba shop). They have an entirely reasonable selection of wines there.