Well you have a few options:
1. Your husband stays in Mexico with you while your application is in process. He will need to submit proof of intent to re-establish himself in Canada e.g. submit plans of where you will live, where he will apply for work etc. A declaration from family members offering you financial support until you get yourselves settled is also good.
2. He returns to Canada and you stay in Mexico.
3. You apply for a tourist visa and return to Canada together. You are definitely eligible for a temporary visa, but you should be aware that you are not likely to be successful in getting one. Tourist visas are often denied when you have a spouse in Canada since with a TR you are expected to leave at the end of your visa. With a spouse in Canada, it will be hard to show that you really intend to return to Mexico.
As far as getting your marriage "legalized", that isn't necessary. If you are legally married in Mexico, you are legally married for CIC's purposes. You don't need to do anything further, though of course you will need to submit a copy of your marriage certificate with your application.
Good luck.