I don't know if this will help you but this was posted a while back.
Direction for buses from Punta Cana to Santo Domingo
This express departs every day from the Sitrabapu Terminal that is beside the New Politur Police Station in B?varo (Punta Cana), near the Friusa crossroads. The coach departs at 7:00 - 10:00 am and 2:00 - 4:00 pm daily. The one-way fare is RD$ 230. The ticket office to the left of the building behind the banca. Tickets are sold on a first come - first serve basis. Plan to arrive at the ticket office ?-? hour before departure to secure best chance of a seat. It is about a 3.5 - 4.0 hour trip from B?varo to Santo Domingo. The coach trip is comfortable and just as reasonably safe as in a taxi but cheaper.
There are two main stops in Santo Domingo - Parque Enriquillo in the middle of the downtown commercial district (advise not to arrive after dark ) and at the terminal at the corner of Juan S?nchez Ramirez and Ave. M?ximo G?mez near the Nacional Supermercado and just a short distance from the National Theater and the American Consulate
Note: People who desire to go to Las Americas airport from B?varo may request the bus driver to stop at the crossroads to the airport. There is a nearby taxi stand where you can obtain the 1-2 km ride to the terminal.
This was posted by PJU on 2 November ?05
So you just do it backwards!!!
As for how to get to Santo Domingo from Santiago...the information you have is accurate. Taxi (RD$450-500) into Santiago Metro or Caribe Tour station (they're onthe same street), bus to Sto Dgo...
Good luck!!
HB
alternative plan: Hire JJ and your are there quick and safe. email his wife at this address
palomalinda0890@hotmail.com
Roc?o will tell you prices and time, and you can compare...