Do I need to file I-864a if my US Citizen wife is not working?

[MrCool7]

Hi all, thanks for awesome advises here. I'm currently on H-1B status which will be expired on November 2017. My wife is a US citizen and we married 2 years ago. We're filing papers for my Green Card. The problem is my wife hasn't worked for 2 years, she quitted her job to take care of our baby. My income is high over the poverty guideline for a family of 3. We filed a joint tax return last year for 2015 tax year. Could anyone please let me know if my wife can sponsor me for Greencard with no income? and do we need to file I-864a? Thank you and I really appreciate your help.