The best diving from Provo is generally considered to be at West Caicos, a sort of long boat ride but a common trip done by various ops. There's some diving near the island too. I'm sure you'd have no problems next summer from Ike.
Grand Turk is the other main diving area, the diving is mostly close. I think T&C has pretty good resources but I wouldn't try and guess at this point when things will be back together on GT. I'm sure infrastructure will be ok but there are no big hotels there, it's smaller inn type places. And you never know if places like that will rebuild quickly, or close for a long time. Salt Cay and South Caicos also have good diving but they got beat up as well, They also had fewer places to stay or dive ops even before Ike although they were starting to get some options.
There's always a liveaboard. The Aggressor and Caribbean Explorer II run from Provo, they dive West Caicos and some of the smaller islands the day boats don't get to much or at all.