Can I still fix my parents' papers if their visa are expired?

Under the law as it is now, you should be able to file immigrant petitions for your parents as soon as you turn 21. You will also need to show that you earn enough money to support yourself and your parents above the then-current poverty level. It does not matter if your parents work and support themselves; as a condition of giving your parents green cards, the government requires you to promise that they will not need public support (Medicaid, SSI, food stamps, subsidized housing, etc.) and to show that you can keep this promise. If you will not earn enough money, you will have to find someone who does and who would agree to become a co-sponsor of your parents. Co-sponsor does not need to be your relative, but does have to be a U.S. citizen or permanent resident. How much income is "enough"? Every year, the numbers go up a bit. Current information is at https://www.uscis.gov/sites/default/files/files/form/i-864p.pdf Count the people in the sponsor's family, add 2 (your parents), and look up the minimum income in the far right column of the table. Now, all this might change. As you might have heard, immigration reform is a hot election issue, and each of the Republican candidates promises to "tighten up" our immigration laws and policies. This is why I started my answer the way I did: if one of the Republican candidates becomes the President before you turn 21, you might be unable to help your parents.