It'll be easier if you don't mind to hire a live-in nanny from SF!
It's hard to find a non-live-in or p/t nanny/helper in your area and my area, I already kinda give up!
I had actually tried to post an ad outside the 99 Ranch Market in both Mountain View and Cupertino Village, where is about 20 mins from my home. Responses were not so good! I think most people live in or near Mtn. View are generally more upscale and they don't usually look for that kind of jobs!
Or, when your kids are potty-trained, you can consider hiring a high school or college student to babysit them.