Reasonable sum to spend on rent for an apartment in Warsaw?

Hi everyone!
My question is: based on average cost of living in Warsaw what sum seems reasonable to you to spend on the rented appartment for a family of two with net income 9000 pln? Mind that it's also needed to run one decent car ( no need to finance it, though ownership costs apply). Also please note that most prefferable district is Mokotow or at least neighbour ones ( I know it's expensive but office is in the Mokotow and it seems reasonable taking into consideration Warsaw traffic to live as close to it as possible)

Any thoughts will be high appreciated.
Thanks in advance!

Which part of Mokotow it is a large area?

Its not about being in the Mokotow (though being as close to the GM as possible will be nice). It is more about reasonable percentage of the income to spend on apartment that will be neither out of budget nor too modest for the budget. Let's say optimal. And being not in the Mokotow at all is also possible. Just willing to spend not more than half an hour to get to work.

GM being Gal Mok, anything below 2,500PLZ per month, you will have stiff competition for above that figure it becomes much easier.