I live in Florida too. If you have room for it, why not get another fridge? I have 4 in my garage and didn't pay a dime for any of them. Seems older refrigerators are easy to come by (especially when you're not looking too hard).
Then spend $90 on a Ranco digital temperature controller and you've got it. Otherwise in the hot summer months you're going to struggle to keep your ales at good temps, even with a swamp cooler.