Your grandmother's last name might still be Krupiak. I've been trying to find out about mine and looking over the Ellis Island site (
www.ellisislandrecords.com) it looks like the Krupiak's all came from Jaworki. I have yet to figure out where that is on a map! My great-grandmother was Xenia Krupiak. Her first name has been spelled as Ksenia, and Kzenia. On the Ellis Island site I think it might be my great-grandmother coming through in 1905, but the real puzzler is that she states that she is married with a baby Julianne. However, Krupiak was her maiden name and the first child that I knew of was her daughter Anna Pronchick born in 1909 (four years later.) Her next daughter was Julia Pronchick born in 1911.
One of the only things that I know of Xenia was that she had a sister who was called Eva born 1886 who married a Stephen Timko and they stayed in New Jersey. Xenia was married and living in Philadelphia by the 1910 census. I do know that Xenia and Eva's mother was Anna Natkowich or Natkovitch.
With the similarities of Jaworki, Krupiak and New Jersey I thought there was a good chance of some sort of connection.