You can check the American Immigration Lawyers Association database here: http://www.ailalawyer.com/. This should help you find a lawyer in the right area and specialization. Immigration law is federal, so a lawyer anywhere in the US could help with the immigration aspect. However, a CA family immigration expert should be familiar with CA divorce law also.
The American Immigration Lawyer Association is certainly a good start. You can also check other Bar Organizations such as the Mexican American Bar Association or the Orange County Bar Association. A search right here in avvo might also provide you with some names.
As the previous answers state, the American Immigration Lawyers Association (AILA) gives a list of attorney's who concentrate in immigration matters. I am a member of AILA. About 25% of my practice concerns immigration matters. I am also an attorney in California concentrating in Family Law (Divorce) matters (about 60%). Since you do not give a specific question, I am unable to respond. But you can set up a free consultation with my office and ask any questions.