moving to Santo Domingo

Welcome to the DR! I'll be seeking the answers to your questions myself within the next few months. But I am a last minute type of person. There is a huge chunk of information to be found at http://www.dr1.com/living/index.shtml

Generally speaking, importing cars and furniture is not advisable. You will be opening the door to a great deal of frustration, anxiety, expense, and disappointment. For example, see this and pick out the threads that have to do with importing http://www.dr1.com/forums/search.php?searchid=30807

Every regular on this board, most of whom live in the DR, will tell you the same: Sell your cars and furniture and replace them in the DR.

However, you mention that your wife will be working as a missionary. Perhaps her church has been able to make special arrangements for importing furniture, etc., that are not available to others. You should investigate this. However, if you find that there are no special arrangements, then I strongly recommend that you don't import.