No Stevie, the buses from the Toll Road station do Not go to Sosua. Cabrera/RSJ is about it. From there it's Carito or Guagua.
You may be talking about the small bus station which is at the entrance to the Santo Domingo/Samana Highway. This is about 15 minutes from the Airport. You would need to take a taxi, which would probably cost about $12-15usd. From there you can probably pick up a Caribe Express to Sosua. You need to CALL the bus company in SD and ask the questions that you have listed above. They should be able to give you all the information.