I am a mexican citizen and a permanent usa resident...do I need a mexican or usa Passport to travel to Mex?

Mexican Passport with your USA Resident Visa to get back in the US

A Permanent Resident of the United States can travel freely outside of the US. A passport from the country of citizenship is normally all that is needed. To reenter the US a Permanent Resident normally needs to present the green card (Permanent Resident Card, Form I-551) for readmission.

Only American citizens may have an American passport...so when you become a citizen, you mya apply for an American passport. Until then you must keep a current Mexican passport. If you do not currently have one, you may apply at the nearest Mexican consulate. See list below.