Here is an organization near southern, CA. They are rescue, not a shelter. If you give them a call, they may be able to quickly direct you somewhere.. whether they can better walk you through how to adopt the cat out yourself (how to make sure you make the right choice for a home) or else know a rescue that has room to take her in.
Best of luck. And it's great to see that you are trying to help her find a home!!
http://www.kittenrescue.org/lahelp.htm#feral