In order to get a green card, you will either have to marry a US Citizen, win the lottery, get an employer to petition for you. Once you finish college, you will get the Optional Practical Training for year. An advance degree could help. Areas in short supply of teachers may be willing to sponsor you. Talk with the DSO to find out what to do as you prepare towards your senior year. All the best!
You should consult with an attorney to review your options for obtaining permanent residency or work authorization through another process (such as deferred action). Often, universities have resources available to international students to give advice regarding these matters. I would start with an international students counselor at your school.
DISCLAIMER: This answer does not constitute legal advice and no attorney client relationsip has been, or will be, created until a valid engagement agreement is signed. No duty arises from this posting. Answers posted here are general and made with limited knowledge of the actual facts of your case. Always speak with an attorney licensed to practice law in your jurisdiction if you wish legal advice specific to your case.
I agree with my colleague Mr. Hernan. Speak with the Designated School Official (also known as the Foreign Student Advisor) for some personal guidance. You may also wish to consult with an experienced immigration attorney as well.
This answer is of a general nature and should not be relied upon as final, nor is it intended as legal advice. A consultation with an experienced attorney is always the best way to go.