I want to know my rights in the said property
Now can i file a case for the flat?
You can very well file a case for partition and separate possession of your 1/4th share in the property
If yes what will be the court fees as i am not that well off?
Whether you are well off or not the requisite court fee has to be paid otherwise the case cannot be taken on file. The court fee aspect differs from one state to another across the country, you may enquire about his locally.
My other brother and and sister are settled abroad so it seems they are not interested OR do not want hassles.
Whether they are interested or not they have a right to a share in the property so they may have to be impleaded as necessary party to the suit.
Whats the difference between civil and High Court
You may search for the difference from google web site
I am sure I have not given any NOC anytime to my father or Society regarding this flat.
If society is not responding to your claims, you may implead them as another party to the suit for seeking necessary relief against them too.