actually, there is one good place to buy fabric suitable for quilting.
It's called Bahama Hand Prints and it is in Nassau. it is not on the main drag, you'll need to take a bus or a car
http://www.bahamahandprints.com/
when I went to Nassau, i was lucky enough to get a tour of the factory out back. they sell cotton suitable for quilting, fat quarter and you can buy pre-packaged yards/half yards.
have fun!