If I understand this, you were previously going to land in Santiago and go to Sosúa, but you all decided, instead, to go to Santo Domingo?
If this is the case, you have to plan on taking a taxi into Santiago, and then catching one of the nice air conditioned buses down to Santo Domingo. This will take you all about 2 1/2 hours if you make the connections. Buses leave every hour, morning to evening...
Alternatively, if you have a small group--3 or 4--you could email Rocío Valerio at
palomalinda0890@hotmail.com and see if her husband can take you directly to Santo Domingo from the airport. It is only about 1:15 to Sto. Dgo from STI airport.
Santo Domingo is a city that parties every day. I am sure that some of the denizens of that locale will be more than willing to inform you of what is what....Behave now!!
HB