Immigration renewal and permission question?

Its kind of hard for me to explain but my husband's brother and sister are currently living in Ecuador and have a green card and residence to be here their residence expires June 9th 2010 and were last in the country exactly 2 years ago and got what they call I guess permission for them to stay in Ecuador for 2 years. They want to come back now on short notice so they won't lose their residence but since its short notice there's not much time is there any way they can p the date that they got permission for and come back later on or if they don't come before or on June 9th its over I know it sounds stupid but its really hard for me to explain this situation since I don't know the actual vocab for immigration laws and rules. Please help....