i'm afraid they are not yet available.
at the moment are available just german infantry and command.
can't wait for polish infantry

Tracks and Troops has them:
http://tracks-n-troops.eu/shop/index.php?main_page=product_info&cPath=14_3&products_id=13325
(But sometimes Tracks and Troops lists things they don't actually have in stock)

And Jadar Hobby expects them on 5th December 2014:
http://www.jadarhobby.pl/first-to-fight-pl193919-172-polish-infantry-1939-p-39481.html

i'll believe them when i'll see them in sprues
hope soon... probably soon, it seems

Very promising much better than the Germans they look like Caesar's figures.

https://www.facebook.com/tankmodels/posts/807173905967328

These are now actually in stock at Jadar Hobby:

http://www.jadarhobby.pl/first-to-fight-pl193919-172-polish-infantry-1939-p-42671.html

And only $6