I've been using one called The Wirie, that I bought for a very good introductory price on eBay several years ago... I've been happy with it, but the price is up there now, and there are many far more affordable options, the primary value of mine is that it's a weatherproof arrangement that can be permanently installed, or left out in the rain...

But the innards of most of these antennas are very similar, usually dependent on a small booster antenna made by Alfa... I've since upgraded my internal antenna to one called a Bear Extender, which has gotten good reviews from MACWORLD. These small, easily portable antennas are not very expensive, I paid less than $50 for my latest one, and know Alfas can be found for considerably less than that. If you protect them from the weather, there's no reason you can't get away with one of these alone, and my small Bear Extender is all I take with me on deliveries, or whenever I'm traveling...

Another thing you might consider, is a cellular plan with a device that permits you to create your own wifi hotspot aboard, using cellular... Others here will know far more about this arrangement than I, but at least while you're in the States, that could be a good way to go. But I would guess it would be prohibitively expensive in the Bahamas, but that's just my guess. Besides, you're probably like me, in feeling that one of the reasons for going to the Bahamas in the first place is to get AWAY from the freakin' internet for a spell... (grin)