Did she have a spouse, or any other relatives living with her that you are aware of? I would start with them, and try to find them on www.whitepages.com. From there, I would go to the Background Check Gateway http://www.backgroundcheckgateway.com/ and see if she is listed, if she's dead, it should have a date of death. If that does not work, try the obituaries for 1997 for Jeffersoncity Missouri, they only keep the last year online, but there are hard copies available in the state of Missouri I am sure.
Good luck in your search