If the estate is worth less than $150,000 (sounds like it is, if $11,000 bank account is the only asset), then you can file a small estate affidavit under California Probate Section 13100 (and following sections). Contact an attorney to prepare the affidavit (you'll also need a death certificate, and some other documents).
If you are the only heir, then the California Probate Section 13100 form will be sufficient. Google the small estate declaration 13100 and there are several forms online that you can use. You will need to notarize the small estate declaration and provide a certified death certificate Follow the instructions on the unclaimed property site. It will be a slow process but eventually you should get the money. Best of luck.