I suggest getting her death certificate from the PA Dept of Health. It will list where she is buried and exactly when she died. You could also check with the cemetery office where her sons are buried to see if she is buried there. The church she was a member of may have something in their records. The Diocese of Scranton might also be able to help you if you don't know which particular Roman Catholic church she was a member of. They may also be able to direct you to which cemetery if it is not the same one as her sons. Lastly try the Genealogical Research Society of Northeast Pennsylvania in Olyphant, PA.