Also trying to trace my Family (Warsaw)

I have had no contact at all with the Polish side of my family. My father said very little about them, In fact I know very little information about them. I know he was born in Sosnowiec.
Does anybody out there know where i can go to try and trace any existing members, bearing in mind the very little information i have. My father died 29 years ago, so any more information is lost to me. I appreciate any help at all because I have been looking for some clues for years.