Sitter Job in Los Angeles, California

We have two daughters, ages 9 and 5, and I just need a person I can turn to for help when my husband is working or traveling. It would be anything from simply being with them so I can be out (and helping them with homework and/or meals as needed) to helping me chaperone them to after school activities. We also have a 1 year old dog (a lab-dane mix) - no job responsibilities other than perhaps letting him out into the yard - but he's a big dog and we need someone ok with that.