If your wife is Mexican, you will need to start family petition for her green card. Is the daughter your biological or step? IF step, you need to invite her as well. If biological, you need to report her birth to the embassy.
You may need to file a waiver depending on the circumstance. You should consult with an immigration attorney.
You should consult with an family law attorney. Immigration status does not influence a person's ability to collect maintenance. Whether the wife is entitled to maintenance is the question you must ask to the family law attorney. Good luck!