How can My wife and I adopt My sister in-laws child?

My sister in-law lives in Chicago. Me and my wife live in Las Vegas. She wants us to take her 7 yr. old Daughter and we want her. We can provide her with a better life. She is willingly giving up the child doesn't want her anymore. Does anyone know if there is a fast way to adopt her? Or what steps need to be started to get the ball rolling?