Backup Babysitter For 2 Cute Girls

I'm looking for a great babysitter for 2 sweet girls, 6 and 8 yrs old. We currently have a nanny that comes regularly but I am looking for a backup that is available when she is not. I am a single mom and would like to maximize my time with them at home. I need someone who could pick them up from school (they let out walkers in our neighborhood - 2 min walk). I'd love someone who can let them be kids and assist with homework until I get home rather than in an afterschool program. I'd love some light tidying, help with laundry. Would also need help with transporting to activities. We have a sweet and playful dog also. I get home around 4:45 - 5:15.