Your father's church baptismal record should have his parents place of birth. If your ancestors were naturalized citizen and/or had social security numbers than those documents would have a place of birth.
few sites for research:www.rootsweb.com/~polwgw/index.htmlwww.pgsa.orgwww.polishroots.comwww.surnamenavigator.orgwww.ellisislandrecords.org
distribution of JANKIEWICZ surname holders in Poland:http://www.moikrewni.pl/mapa/kompletny/jankiewicz.html
map of Poland's wojewodztwos:http://www.geneteka.genealodzy.pl/