If Margaret was baptized in the church around Kilnamanagh which would be Ballinameen/Estersnow/Kilnamanagh records do not start until November 1859. I did find an 1852 baptismal record in Boyle RC parish (see below) which is the parish just to the north of Ballinameen. Do you know her mother's name?
Name:Margaret FeelyDate of Birth:
Date of Baptism:12-Feb-1852Address:Not RecordedParish/District:BOYLEGender:FemaleCountyCo. Roscommon
Father:James FeelyMother:Mary HanlyOccupation: