hi as far as i know babies who were born 0-3 months could enter here even without visa, your wife should get her passport first then submit it to the immigration or whoever will arrange if for you. you should fill-up the form a family visit form then comply all the requirements..like her passport copy, your passport copy,babies passport copy, your salary salary certificate, your affidavit of support sealed by the your embassy..

better if you inquire to your PRO about this matter im sure he can help you a lot!