You can order her application that she initially completed for the card , which should tell where and when she was born, her address at the time she filled out her application, and her parents names. However, two things you should know- if the state she died in has restrictions on what information can be released, parents names on the ss application may be blocked out when you get it. Also, if her death was never reported to the social security administration, you will need some proof of her death.
This tells you how to request the application.
http://www.ssa.gov/foia/request.html#a0=1