Sorry, "CUL" is Cost U Less??? Yes, they do sell wine and beer. However, if you get to Cost U Less, I would go to Grand Marche, across the street. They have a lot better selection of everything and generally smaller packages than Cost U Less.
As far as within Simpson Bay, unless you want something pretty specific, go to Gourmet Marche. Cheaper prices in general than Market Garden, especially for liquor and wine, although Market Garden does have a larger selection than Gourmet Marche and is a tiny bit closer to Simpson Bay Resort.