Can I still petition my fiance in the Philippines?

Significantly more information is needed in order to provide a legal analysis. Nonetheless, if you are a U.S. citizen you may be able to succeed in petitioning for your fiance to come to the U.S. to become married to you within the required time, and then to proceed with an adjustment of status application so that he may become a Lawful Permanent Resident (to get a "Green Card"). This is true notwithstanding that you now are a single mother. There really is no substitute for you and your fiance to consult with an immigration attorney who, after learning all of the relevant information, could advise about eligibilities, options and strategies to attain your goals, and who then could offer legal representation in the often complex application process.