Share internet connection between 3 computers

Our college provides Internet connection through Ethernet LAN cables. Now I have only one LAN port working, and would like share this Internet connection with my room mates through wi-fi (preferably). Also the LAN works on some specific proxy setting. But I don't know whether I have to provide the same proxies to the other computers. Also windows 7 asks them to assign ip addresses for which I don't have any idea.

I would like to know a step by step approach to share my LAN connection with two other computers through wi-fi. All the computers run on windows 7.

Please Help, Thanks in advance