Judy, On familysearch.com, there is a Peter SCHWENK from who married an "Anna," which could have gotten changed to "Hannah" when they migrated to the U.S.That marriage is pretty early for your Sarah Schwenk's parents, though.You also might want to consider trying alternative first names in case Peter or Hannah went by their middle names."Johan Peter" was a popular choice for German names, for example.Good Luck wtih you search!
PETER SCHWENCK Father: JOH. SCHWENCK
Spouse: ANNA CATHARINA ALLMANN Marriage: 24 FEB 1767 Evangelisch, Kirchenbollenbach, Rheinland, Preussen