Port Forwarding and IP Address...

[BEN_UK]

Hello,

I have got a NetGear wrg614 v6 and my Xbox 360 connected together with rj45 cable.

I need to open theres ports on the router for the xbox360, 88 & 3074

So i opened them for the IP the 360 is connected with which is 192.168.1.2

Now though the IP had changed to 192.168.1.3 and my computer is 192.168.1.2.

How can i get the 360 to stay on IP 192.168.1.3 so the correct ports are open
?

Thanks Ben