I have an ibook pro mini laptop which i brought from tvc skyshop. I want to start internet on it. But it has internet facility only through wifi not by dongle or mobile. I do not know about wifi. Please tell me how can i run internet through wifi, what things i have to buy.

It is not clear, what is source of your internet connection ?
Is it Broadband or something else ?

The source of my internet connection is broadband.

If your WIFI router is set to assign IP address automatically then all you need is to turn on WIFI in your laptop and then make sure it is set to get IP address automatically.

Are you using your WIFI net in any other device, if yes then how you connect it to WIFI ?