The indian currency is the rupee. There 45-55 rupees per US dollar.
Change your money into rupees at the airport, just after you get through customs with your baggage. Banks may give better rates. Hold onto your exchange receipts; if, when you leave the country, you want to change a large amount back into your country's currency, you may have to show these receipts. Acceptance of Foreign Exchange by unauthorised persons is strictly prohibited under Indian Laws. Change money only at the banks.
There is a branch office of the State Bank of India in the Prasanthi Nilayam itself, and there are several other banks outside --Canara Bank, Syndicate Bank, Vyasa Bank, etc. General hours are
Monday-Friday, 9.30AM to 1:30PM
Saturday: 9:30AM to 11:30AM
All banks have foreign exchange facilities and will accept travelers checks and credit cards. Some of the banks are supposed to have ATM facilities.