Firstly, check your resort.
Very likely they will not allow unregistered guests, the term is, "not chica friendly".
It is often cheaper to book a package at an all inclusive than flight hotels meals separately, maybe a time share is available to you, or it is a family event. We won't judge, but we would not make that our first choice.
Secondly, dont panic.
Public (shared ) taxi will cost about $1-$2 to Sosua from the main road in Puerto Plata. Dolls Secreto is a Cabana (short term hotel) that is a $1 moto ride from the strip and costs about $15 for 4 hours. There are more Cabanas in Puerto Plata and a few other short term places. Private taxi I should imagine is in the $25-$35 range each way.
Or... If you plan a big day or two, rent a room in walking distance to the strip at Seabreeze or Hotel Europa for less than $40 a night.
If I was going back and forth to Puerto Plata (and going easy on the booze) I would rent a car.