Moving to Calcutta

Hi, I am looking to move to Calcutta in the next year, I have already been once, coming again in November. A few questions, wheres a good place to live (I will be working in slums, so not to far away, but also far enough away for a break), how much money is needed (been living in Uganda as a missionary for the past 2 years), are there any expat groups out there? Any other info gratefully received.