Everyone has encountered the same problem. NEVER go by family stories since much of the 'information' changes from year to year, depending upon who said what and when.
"She is the only source for family history during that time period, and family history essentially ends with her."
Absolutely not true. Tracking your family history does not depend upon any relative giving you the information. It is all up to you, building your tree starting at you, working back to your parents, grandparents, etc., by getting documentation (BMD certificates, baptismal information, marriage records, etc.)
Go to your local library and get a couple of books on genealogy/doing family history and follow the advice and steps. Take a look at Ancestry's and FamilySearch.org's free research guides. When you get stuck, post queries on these boards. Be sure to follow the advice given in Board FAQ.