You need to fax a form (I130 Lawful Permanent Resident Upgraded to USC Fax Sheet) to the California Service Center (CSC) to notify them that you are now a US Citizen. If you have an attorney who is a member of AILA (American Immigration Lawyers Association), he/she can obtain the form for you through the AILA website.
If you don’t have an attorney you should contact the USCIS National Customer Service Center at (800) 375-5283 for assistance – hopefully they’ll be able to help you.
Edward Weiner
Attorney at Law
E-mail: E.Weiner@immigration-aux-usa.com
Internet Site:
http://www.immigration-aux-usa.com/