Babysitter/help for early evenings & occasional weekend work

We're a family of four with two little girls. One is 2.5 and the baby is almost 7months. Daddy travels a bit for work and Mammy will be going back to work soon. We're looking for someone to help maybe 2 evenings a week from 5 to 7 or 8 to start. Mammy would be home as baby is still very small. What we'd like is for someone to get to know the girls and help with bedtime especially as with a dependent baby bedtime takes two people. Occasional weekend work too. We'd like someone who has worked with small kids and can become part of the family, who we can call on when we need help especially when we both return to work. We're based on St Mary's Road so quite central.