History / Pre war Polish land owned by my grandfather - where can I find the maps? [20]

hi everyone .. just need to find out abt polish land laws we have found out that we own a plot of land bought by my polish Grannie and Grandad in the 1930s and someone in Poland not a family memeber wants to buy it and says that we have to make up our minds fast before Dec 2008 whether t sell it or keep it....? or the govt will take it,,,,, if it remains unclaimed

What is the rush .... ?