I googled Kingston NY Home Brew and found a few references to try. I wouldn't be too hopeful though. Its Sunday too, so any commercial place would be closed. Try the nearest soda fountain, maybe in Saugerties or Woodstock or Catskill.
If you want to drive 2 hours, I can give you one. Party creations is a homebrew store that have them in Red hook ny. They are closed but they run the shop from their house maybe they might answer the phone. They are probably 1 hr away