We were in Punta Cana last April..... we stayed at the Bavaro Barcelo Palace which was quite nice. However, the only dive shop that I could find on that portion of the beach was "Dolin Dive Center", about a mile up the beach. Frankly the diving in Punta Cana isn't great.... you have to go north or south.
I actually did my OW dives with them, having completed my book work back home on Oregon. Let me tell you, it was a real expirence....They picked me up along the shore in a 12 foot wooden boat without any ladder and with an old Merc 1950's motor. They took me out to some dive spot abut 1/2 mile off shore and me and this other guy backrolled in. (remember this was my very first open water dive) We were in surge and current, that sent me out from the anchor line like a flag in the wind. I passed my test, but the dive will stay in my memory forever.
If you get the chance, head south down the Catalina Island. It is worth the money, and time. I did my second and third dives there and I remember doing my first wall dive on the reef around the island.
I have some great pictures of the beach and the area if you want to see on Web Shot under Philtobin6625 Have a great time and good luck finding a good dive shop.
Phil