Money Management

I am a developer with a full time job in India, how can I earn extra money to save for a house downpayment?

I want to gift a house to my wife on her b'day next year, but currently I don't have any money. With my full time job I can only manage to fulfill monthly expenses. I work six days a week, with Sundays off. I am on an employment bond, so switching jobs is not an option at this point. What should I do to earn INR 10,00,000 ($15,500) during the next year so I can afford the downpayment of a house?