i personally think 2 days in Krakow is not enough. There is a lot to see in the city, and there are several interesting day trips. I'd spend more time there and less in Warsaw.

To put it in perspective -- think of Warsaw = Milan, Krakow = Florence. Although not a perfect comparison, there really is much more for a tourist to see / do / experience in Krakow, which is just a gorgeous little city. Not speaking Polish was not a problem at all for me.