Don't think it is in use at all now. I recently got my PPL at Prestwick and we used to train over the Turnberry area. As far as I could see, it was as a previous reply mentioned, now overrun with golfers. We were always told that we could use it in an emergency but I would not want to land there in anything BUT an emergency. The only remaining obstacle free runway is in a dreadful condition. I think that helicopters can land near the hotel though.
Best idea is to land at Prestwick. It is only a couple of minutes down the road by car from the Turnberry Hotel.
Phone the Prestwick Flight Centre 01292 476523 for all the latest info (I believe we are getting controlled airspace soon!)