Babysitter Needed for my Children

I have 2 littles ones - 4-year-old boy and 1-year-old girl - who need to be picked up from preschool at 2 p.m. and cared for till at least 5pm, maybe a little later, so that I can work. There may be occasional babysitting needs, and availability in the mornings might be an added bonus in the future, but not required at this time. I do have two older children - 13 and 10 - who do not need care, and an australian shepherd.