I recommend a site dafont.com , there I found fonts with Polish letters, which are: American Typewriter, Andale Mono, Arial, Arial Narrow, Arial Unicode MS, BlairMdlTC TT, Calibri, Cambria, Candara, Century, Chaparral Pro, Cochin, Consolas, Constantia, Corbel, Courier, Courier New, Didot, Earwig Factory, Franklin Gothic Book, Franklin Gothic Medium, Futura, Geneva, Georgia, Gill Sans, Gill Sans MT, Gill Sans Ultra Bold, Handwiritng - Dakota, Helvetca Neue, Herculanum, Hoefler Text, Kozuka Gothic Pr6N, Lithos Pro, Lucida Grande, Marker Felt, Menlo, Microsoft Sans Serif, Minion Pro, Palatino, Rockwell, Skia, Tahoma, Tekton, Times New Roman, Trajan Pro, Trebuchet MS, Verdana, Zapfino, Adobe Caslon Pro, Adobe Garamond Pro, Apple Chancery
All of them have Polish letters and on this site there are symbols near fonts which show you if they will work on Mac or Windows, I hope this helps :)