Nanny/Household Aid

We are a family of 4, soon-to-be 5! We have a newborn coming in July and have two other boys aged 18 months and 3 years old.
We are looking for someone to help me (mum) mostly, but my husband will be around in the evenings as well. Hours are 2.30/3pm - 6.30/7pm on Monday, Wednesday and Friday (days are negotiable for the right person) for three months.
Duties include:
putting on, hanging out and/or folding the laundry prepping/cooking dinner (either a bargain box type thing or a simple meal) helping with the older boys when they come home at around 4.30pm - unpacking daycare bags, playing with them, feed them dinner and help with the bath general tidying (light vacuum, tidy toys, not any real cleaning per se)
My husband and I will always be home, so this is not a sole-charge role. It's really to help me out with the older boys and some household duties whilst having a newborn baby.
Child-care experience isn't necessarily required, but someone who likes kids and is pro-active is a must.