It sounds like you do not have enough information on Jan.
I think your best bet is contact the county genealogical society for where your grand father and aunt were born.
They might be able to suggest a Polish genealogical society in the area. If you haven't tried these:
The Federal courthouse for naturalization papers . These list everything.
Baptism records at the Polish church in the area. These typically list parents name and their birthplace. Maybe even grandparents.