If she went to Cuba, she came back to US, but I have a feeling you have this info.
Unless you find a church record you will not find her birth record.A death record might provide some info, but she probably died too early to have DC available. SC records aren't going to help you until you know her birth name. I suggest you try and track her ch b Cuba...Angeline?; Frank?
Name: Margaret Mouton Event Type: Census Event Year: 1860 Event Place: The Town Of Howard, Brown, Wisconsin, United States Gender: Female Age: 63 Race: White Race (Original): [Blank] Birth Year (Estimated): 1797 Birthplace: South Carolina Page: 28 Household ID: 199 Affiliate Name: The U.S. National Archives and Records Administration (NARA) Affiliate Publication Number: M653
Household Gender Age Birthplace Angeline Bourgouine F 40 Cuba Louis Bourgouine M 18 Wisconsin May Bourgouine F 16 Wisconsin Eteene Bourgouine M 15 Wisconsin Caroline Bourgouine F 13 Wisconsin Devet Bougouine M 11 Wisconsin Josephine Bourgouine F 8 Wisconsin Margaret Mouton F 63 South Carolina Leonor Martineau F 21 Cuba Anthony Martineau M 2 Wisconsin Claressa Martineau F 0 Wisconsin ===================== 1870 Kenosha WI Household Gender Age Birthplace Frank A Moulton M 31 Cuba Gertrude Moulton F 23 Saxony Margaret Moulton F 66 South Carolina