1) You do not need to marry in the DR as you US marriage is legal. 2) For your wife to obtain residency she qualifies as she is married to you and she needs to go to the Dominican Consulate nearest to you in the US to obtain a residency visa (hand over a load of paperwork) and then come to the DR to complete the process at the Migracion office in Santo Domingo. The list of documents required are roughly:
• Your passport which should be valid up to the date you are expecting to return home or longer.
• Passport size colour photo with a white background, hair off the face and not wearing earrings.
• Where appropriate birth and marriage certificates. These should be the long form in countries where they also issue abridged versions, should be issued within the previous six months, apostilled, or legalized in those countries which are not signatories to the Hague Convention (such as Canada) and translated into Spanish. The translation should also be legalized.
• A medical certificate which can be issued by your General Practitioner and must certify you have no contagious diseases. This should also be translated into Spanish.
• A Criminal Record Check from your home country which should be apostilled and translated into Spanish.
• Proof of income which can be bank statements or a letter from the bank, rental agreements or a pension letter.
• A copy of your local identity card such as passport, driving licence or residency card.
• If any visa request involves minors traveling alone, the authorizations of both parents or legal guardians must be provided in a notarized document with their signatures. It should also be translated into Spanish.
• Most visa requests require a letter, in Spanish, addressed to the Consular Section, including your name, address, nationality, occupation and reason for visiting the Dominican Republic.
Matilda