Assuming you are trying to gt an ITIN or SS# the following statement from the directions seems to imply that the document can be certified in the US. I would call and ask.
c Have the copies notarized by a U.S. notary public legally
authorized within his or her local jurisdiction to certify that the
document is a true copy of the original. To do this, the notary must
see the valid, unaltered original document and verify that the copy
conforms to the original. Consular offices at U.S. Embassies and
Consulates overseas may not certify true copies of foreign public
documents and will refer applicants to the foreign authority that
issued the document.
If not you will have to contact one of the various Dominican consulates in the States.