How long will it take to get a Green Card for my mother, who is an Indian citizen?

More information is needed in order to provide a legal analysis and estimate of application processing time. For example, is your mother now located in India, in the U.S., or some other country? If your mother is in the U.S., what are the details of her entry? It would be wise for you and your mother to consult with an immigration attorney who, after learning all of the relevant information, could advise about eligibilities, options and strategies to attain your goals, and could estimate application processing time, and who then could offer legal representation in the often complex application process.