We were there in November, and we were able to buy some adult beverages in the sundry shop in the clubhouse and bring them out to the pool area. They weren't made-to-order frozen drinks, but they had the frozen pouch-type premade (margarita, pina colada, daiquiri) drinks in the store's freezer cooler. What ended up even easier for us was making our own cocktail in our townhouse (right across from the clubhouse) and bringing it with us to the pool.
Windsor Hills is awesome, though. I highly recommend it. We are going again in October! Can't wait!