Linkage wrt54g2 wont let me reconnect

Question

I was connected for the past month with no problems and today, out of nowhere, the router dropped my laptop connection. I tried to reconect and restarted my computer and everything, but it just didn't connect. I checked my iPad and it was connected properly and I was surfing the web with it. I tried accessing 192.168.1.1 and I proceeded with the password only to route to a 500 internal error page. The Internet was still working with my iPad until I decided to try to disconnect from the router and reconnect only to find out that the same thing has happened to my iPad. I want to know what happened and how can i prevent this from happening again? How cam I fix this? I can restart the router, but I don't always have access to it since it's not in my room.