a wlan to lan problem

hello …
i have an existing lan in my office, connected to an outside BIG network, and i want to add wireless connectivity to my office, i have a linksys router, i connected it to my lan (lan port not internet port),and turned on wireless on it, i configured the router with the ip 192.168.0.1, and turned the DHCP on, connected to the router and everything is ok till now, i configured the router with a lan IP 131.107.1.64(outsider lan), and with the correct subnet and gateway and to work as a router(not gateway), but i still can’t connect to the internet through the wlan, where can the problem be ???

notice : we have a proxy installed on the main server but i don’t know if i should put it on the router or where to do..
thnks