The law in your area is the same as the law in all of California, with exceptions as to how much one can possess and cultivate (which is regulated by local jurisdictions). Proposition 215 and SB420 permit you to legally use medical marijuana, provided that your doctor recommends it. You must have "... any illness for which marijuana provides relief".

Your best bet is Medicann. 1-866-mdcnnbs.

PS- If whomever is obtaining this cannabis permit isn't legit, be advised that the law won't treat him kindly if it goes to court or if the person is caught dealing/distributing the weed. Don't abuse the system like so many people do and everything should work out fine.