There is an orphanage assisted by Le Profe and the Catholic Diocese, being run by Venezuelan nuns. It is located near Sosua, near Puerto Chiquito. Perhaps you contact Le Profe (here on dr1) and she will help you with introductions and a list of needs.
Know that orphanages in the DR are not always like those in other countries. Many children are dropped off by parents or friends when they are unable, for one reason or another, to care for the child. If and when circumstances change, they pick up the child and bring him/her back home.
The old folk's home is off Avenida Circunvacion. (spelling?) Pass the public hospital on the left. Pass the road to the cable cars. At the bottom of the hill just before leaving the city and reaching the university, there is a street light. On the left hand side of the road is a small street that heads up a little hill and the old folk's home is on the right. When you get in the area, stop and ask and someone will give you better directions than my pitiful ones here.
The old folk's home is self supporting. They always need bed linens, rice, soap, and the basics necessary for every day living.
I think Hillbilly's advice is well taken. Don't just arrive unannounced. They won't appreciate it, I believe. These are not places for sight seers or well wishers who have no knowledge of cultural sensitivities or intent for ongoing support. Please forgive me if this sounds harsh. It is not intended to be.
Lindsey