@Polsyr: the problem with interacting with Poles who are studying foreign languages is that they always want to practice their language skills so it's difficult to learn Polish with them ;)
That is correct.
how are may chances of staying in Poland permanently once i have learnt the language
I assume you are from outside EU. If you graduate from a Polish university you might be eligible for a temporary residence permit (not sure about the duration though) to allow you to look for a job. You need to make sure that by the time you graduate, you have learned Polish.
Also, assume you will not be able to work and earn money while studying, so unless you have enough financial resource to sustain you during the entire course of your studies, I suggest you look somewhere else.
society in the campus is it friendly, are you a student there.
The campus is a great social environment, and no, I am not a student there but I know someone that teaches there (and therefore I visit there a lot), and one of my very best university professors was a Politechnika Warszawska graduate.