Hi Ms Chopra,
This is a good cause to adopt a girl child and even better now as female population ratio has reduce globally. I fully understand your concern of having a child when you could not bear one due medical reasons.
For adopting a child in India a quite a tedious process and a foreigner, it is lot more difficult. This situation has come as law enforcement agencies are having hard time in controlling child prostitution and flash trade. Thus, there are many restrictions all over India for adopting child.
I would suggest to go slow in the process of adoption from India. First of all you should consult by writing letter to Child Welfare department on Central Government and let them know your intent of adopting a female child. This will protect you in the event of any problem on later stage legally. They also guide you about exact place and agency to be consulted upon.
You may come here in India and search for centre who working for such work of adoption. This may solve your problem without much difficulty.