I have Anna Mary Catherine as her name, but I checked the Michael W. Lau, "Descendants of Christian Lau" and Keith A. Dull, "Early German Settlers of York County, PA" books and they have only "Anna Mary" as her name. They do supply a birthdate of March 3, 1738 for her, so I actually looked up entries in the Dull book for surnames the Laus and Eysters married into during that generation. So I looked for daughters born March 3, 1738 for Gentzler, Sprenckel, Eyster, Rennoll, and Kerber. I didn't find any, but that may be what we have to do to then find other clues about her surname.
Another suggestion is to get Christian Lau's will and read the surnames listed, particularly anyone he owed.
Please let me know if you find anything - I'm a descendant of that branch (and another), too!