There are many font banks out there. But where I can fonts with polish characters ?
If you have your polish fonts, you can generate your font-face easily
I don't know what Polish type foundries there are, but any Unicode typeface should have Polish characters, I beleive. Here's a list of free (as in speech) ones you can use with the FontSquirrel generator goker.cebeci linked to:
However, it should be noted that Unicode fonts are typically much larger than regular fonts because they contain so many glyphs. There are font editing tools that let you remove unused glyphs (generally a bad idea, but may be excusable in this case), but you'll need to ask those questions on the Graphic Design StackExchange site.