250 PLN for a room is rather impossible. I think that current medium prices are around 400-600 PLN. It is cheaper in dorms, but usually you have to live with someone there and dorms aren't/(weren't in my student period) easily obtainable. But sharing room with some cool company during studies is rather advantage in my opinion. In late 90' it was possible to live as a student on about 700 PLN in Wroclaw. Now, I would say it has to be at least 1000 PLN, and considering you are a foreigner (so your supporting family net will be far far away, you know, you wan't get 2 kilos of cakes after some family event and bring it to Wroclaw..) you need something around 1200-1500 PLN per month.
if there is someone thinking about traveling to Lisbon I can help
Actually I considering this in the begining of May :-) but it is unconfirmed yet :-(.
So, I will not bother you now