I think you mean WEP and not WAP. However, if possible you want WPA and not WEP. WEP's not very good at all.
You need to log into your router's settings pages. Still have the manual? It should tell you there -- basically you open your web browser and type 192.168.1.1 or a similar number (may be 192.168.2.1 perhaps...). Then, you type in the default username and password, and then goto the security settings page for wireless, and enable it. You'll need to give it a password, that you'll also need to set on your laptop too.