Hola! Bienvenido a MMM! (Aprendiendo un poco español, pero por favor, ser amable conmigo ;) )
It's difficult to give detailed insight since I'm from the US and a lot of the common places we find savings are or may be more difficult in Mexico. You do have good headroom to save once the debt is gone, and it seems it will all be gone by the late summer. After that, you can easily start putting that 2500 away into savings. Add to that anything you can shave off of the baby expenses, which it seems will be going down soon as well.
I know electricity is quite expensive in Mexico, but this would be a relatively high proportion of income in the US. Would you consider this a place you could find savings?
Transportation is also huge, as is the time spent commuting. Is there any chance of moving your family closer to work or finding work closer to home now that you have good experience? Bravo on your work experience so far, and in a skilled profession-- is there a market in your local community to be entrepreneurial with these skills, and do installs, troubleshooting, network setup, etc.? We here at MMM love the "side hustle," and to me, Mexico seems to have a lot of opportunity for small businesspeople willing to work hard.
Food also seems high, though I understand that food is more expensive in some ways there. Can you reduce this budget by cleaning up your family diet?
I can't say what the right investing options are in Mexico, but it seems Vanguard has some excellent options that match the ones many people here use in the US:
https://www.vanguardmexico.com/institutional/mexico/home.htmSpecifically, the US total market index, Total world stock, and total bond market funds are available to you, which means you can do the same exact three fund portfolio that a huge number of us are invested in:
http://www.bogleheads.org/wiki/Three-fund_portfolioThat Vanguard site is for institutional investors, but perhaps you can access the same tickers either through your employer, through another broker, or through their cross listings on the Bolsa.
Personally, that's what I'd do (and do do).
Buena suerte! I look forward to seeing how it goes for you. I love Mexico, and have considered some places in Yucatán and Guanajuato as possible places to retire...
EDIT: Your english is very good! Have you considered connecting with the Canadian and US expat community to provide professional IT services, assistance with phone and internet service issues, and other tasks involving navigating bureaucracy that Americans with limited Spanish ability would find very difficult? I suspect you could charge far above what you might charge a fellow Mexican, but still have that rate be a great deal to someone from the US/Canada.