If the laptop works elsewhere it sounds like it's a problem with the router or your configuration on either end. My suggestion with wireless hardware is to reset everything on the router. Leave it completely open and try to connect to it. If you can (as in connect, get an IP, log into the router's config page) then you know it all works. From there, start adding your security measures one at a time.
As for changing IPs and such, assuming you mean the local IP, it all depends on the router's software. Most all should have some setting somewhere within the config site to set what IP address it uses.