If you are self-motivated......(longwinded, I admit)
here's a suggestion about learning Spanish. Save the money you might pay for formal lessons--instead buy the tapes and books that are the published versions of the Foreign Service Institute's intensive language study courses. This is a US Gov't agency charged with teaching language to diplomats and others entering foreign service. They are published by Barron's, I think.
They are without question the best way to learn foreign languages because no matter how good the local teacher might be, the fact is that you need to drill repeatedly and consistently to get the pronunciation and rhythm correct. You really need to have tapes to do that.
I was trained in French by the Foreign Service Institute method before going to the Peace Corps in West Africa well over 30 years ago. My French is still very good because the training method created the language equivalent of muscle memory that a good athlete only gets after thousands of drill-like repetitions.
It would take an exceptional teacher to be able to duplicate the quality of instruction in these tapes. You will get all the interpersonal fun stuff you want in the day to day life on the island. Yes, Dominican Spanish is not the same as what's on the tapes, but never fear. You will be so motivated by the desire to communicate with the people of this great place, that you will gain fluency very fast. TV will help too.
But, I contend that fluency will not happen by taking classes anywhere--you need the mechanical repetition and drill and the ability to practice whenever you want.
Good luck.