trustable nanny agency or personnal references (New Delhi)

Dear all
in a couple of week I will be located in South Delhi, defence colony, New friends coloy or GK I or Two. I am moving with two children since the 1st juanuare. 1 a 3 years old.
I will really appreciate recomendations about this matter. She will care what I love more...
are there any proffesional agencie? how shall I manage the contract with them?
English spoken is a must, and previous experience with expat children will be an added value.