Taxi service at the airport can be very confusing. I highly suggest that you pre-arrange private transportation and have a driver waiting. One and Only also provides this service as a guest of the hotel. You definitely should check with them.
Otherwise, I can assist you in making transfer reservations. The details can be found at http://www.cabovillas.com/transportation.asp.
Good luck and have a WONDERFUL time at the One and Only (my personal favorite hotel). about 8 years ago