What we did last month was dinghy over to a dock near the shopping mall where one of the larger supermarkets is. We provisioned and then brought everything back in the dinghy. Worked out very well for us.

From the mooring dock, you head the opposite direction from the channel entrance there's basically another section to the harbor. The dock is in there. As you enter the section, it is on the port side all the way in the opposite corner.