If you stayed outside of the U.S. for more than one year you may have lost your permanent resident status. You may be able to get your permanent resident status back, but you will need to apply for what is known as returning resident status. In order to qualify for returning resident status you will need to prove that

• When you left the U.S. you had been living there as a legal permanent resident and you had been allowed into the U.S. legally;
  
• At the time you left the U.S. you intended to return back to the U.S.;
  
• While living abroad, you did not lose your intention to return to the U.S; and
  
• You are returning from living abroad temporarily or, if you stayed outside of the U.S. for a longer time (over a year), this was caused by reasons beyond your control.

We accept applications for returning resident status every working day, Monday through Friday, 1:30pm - 3:00pm. Please bring the required application fee (currently US$400 or the equivalent in zlotys), the application form [link http://foia.state.gov/FORMS/visa/ds0117.pdf], and whatever material you have to show your stay outside the United States was temporary and you intended to return to the U.S. in a timely fashion when you left- for example, round-trip airline tickets, medical records, police reports, school records and your old permanent resident card (often called a “green card”), if you have it. The consular officer will review your case and decide whether you are eligible for returning resident status.
If your request is approved, the consular officer will give you further instructions on how to apply for a returning resident immigrant visa. If the application for returning resident (SB-1) status is refused on the grounds that you have given up your residence in the United States, it may or may not be possible to obtain a nonimmigrant visa, depending on whether you have established a residence abroad to which you will return. If your application for returning resident status is refused and you have a petitionable relationship to an American citizen or permanent resident, your relative could also file a new immigrant visa petition for you.