The San Francisco Co. Genealogy has a on-line database. You'll find them at freepages.genealogy.rootsweb.ancestry.com/~obitl/volca.html Scroll down to San Francisco.
There's no guarantee her place of burial will be in her obituary. If it's not, you might want to order a copy of her death certificate from the Assessor-Recorder, www.sfassessor.org/ . Successful Searching!