Powai is a popular area for expats and it will only be a matter of time before you meet people.
There are numerous Facebook and Twitter groups online that provide a platform for communication between expats in India. Perhaps have a browse of Facebook and see what you can find in your area.
Otherwise there is a group called Mumbai Connexions which some of our expats have found useful for meeting new people. You will also find that you meet many expat mums like yourself through your childrens' school. Have a read of some of our Expat experiences in India to see how other expats made new friends in India.
Other websites include the Mumbai Expats Networking Group on meetup.com and the Mumbai Expats Community on internations.org.
The best of luck with your move to India.