Teen Jobs in San Francisco?

Hello, so recently my mom was notified that there is a extremely high possibility where she may be laid off due to the budget cuts. I'm 17 of age and was hoping to find a school year job in San Francisco , California. I have been looking over the web, but only to my disappointment that i stumbled across useless job searching websites or websites that abuse the use of private information that i filled in hoping that i would get a job. Would anyone please link me over to a very useful method or at least a website where i may find a job during the school years. From Mon to Wed and Friday i am dismissed from school at 3:16 pm. On Thursday (mostly) i am released at 1:25, sometimes there might be changes. I am willing to work about 2 to 3 hours per day on the week days, and 4 hours on the weekends. On Sat i am busy with additional tutoring that takes place during the morning from 9 to 11:45. I am in desperate need, i really wish to help relieve the burden resting on my mom's shoulders. Unfortunately my parents are divorced and i live with my mom, i really wish someone would reply to this answer with some vital info.