You do not need citizenship to live in the Dominican Republic - getting your residency (residencia) is quite sufficient to live AND work here. Please check & make sure that Citizenship is really what you want/need for your particular needs.
Provisional Residencia (rather than the "Temporary Residencia a lot of lawyers are now getting for their clients - this creates some conversion problems & more passing over of money later on down the line) has appeared many times in the archives, so give that a scan first. On the North Coast, Graciela Firmin has a good reputation for getting the job done quickly & without too much effort to yourself (she even takes you down to Santo Domingo if you need her to) & her charges are from about US $1,000. I do not know lawyers on the South Coast so can not recommend anyone there.
Good Luck - Grahame.