How do I file for my mom but am unemployed with two kids 6 months old and a 2 year old?

Generally a U.S. citizen age 21 or older may sponsor for permanent residency a parent who entered the U.S. lawfully and with inspection (such as with a visitor's visa). This is true regardless of whether the parent may have long overstayed her visa and regardless of whether the U.S. citizen child is unemployed. If the U.S. citizen child is unemployed or otherwise does not have sufficient documentable income, then it may be necessary to have a joint sponsor in the application process. Generally any U.S. citizen or Permanent Resident who has sufficient documentable income and who is willing to assume the responsibilities associated with the Affidavit of Support may qualify as a joint sponsor. Of course, there are many other details that determine eligibility. It would be wise for you and your mother 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.