I do not know the rates when you are going .. but I can recommend South Beach http://southbeachbarbados.com/ as a nice newer place to stay. Get a 1 Bedroom and there is a nice whirlpool tub. Good location across from Rockway beach and also there is a 'grill hut' for good local food in the shopping center next door. Stayed there for several months on business and found it most excellent.

NOW when you have a bit more time .. in BGI .. consider a nice snorkel trip. There are larger boats (touristy and drunken) and then the Small Cats with up to 12 people on board. http://www.funbarbados.com/tours/smallcats.cfm that I found very relaxing...

Don't bother renting car (they are US type cars but drive British side of the road) .. cabs are easy to come by.