If you have any family living close to the cemetery, ask them to visit the office (in person, not just a phone call). I have personal experience that visiting the office in person can provide more information than calling them over the phone or contacting them by email. When I contacted a cemetery one of my ancestors is buried by email the only information I got was in their computer system, but when I went in person I was able to view the entry I wanted in their burial book and find out 3 pieces of information I was missing (the day he died, where he died and what country he was born in). Once you have that information, look at newspapers online and try to find her death notice. Just note that not all Canadian newspaper archives are available online.
If you don't have any family members who can visit the office in person, put out a query on this site and see if anyone can do it for you.
I hope this helps.