by Warsaw standards that would be quite good money but from from impressive
It certainly wouldn't be impressive by Warsaw standards, probably not even 'good'. But certainly would be a least decent.
the salaries over there are much above national figures.
Go to somewhere such as Przemysl and you'd have trouble spending 10,000 a month; even on the old town square there a beer is under 3zl! Here in Warsaw it's pretty easy to drop a grand on a meal for two and a few drinks afterwards (more if you go to Amaro's for the meal) but in Przemysl you'd be pressed spend more than a couple of hundred.