I tried this place, they ask for a subscribtion (~10 000 RD), and for monthly pay as well (~1000 RD), which in totally it's too much since I'm looking just to play several times until middle of November.
Anyways.. Juanita, thanks for a suggestion!
Try finding a number for the Dominican Federation of Table Tennis. I am sure that they have a place to practice. Also Try to get a number for Mario Alvarez who is a major instructor.
The Dominican Olympic Committee has these numbers.