I'm not familiar with your particular router but you should find settings in te Firewall to exclude the use of certain sites and/or at certain times of the day.
To get into the router's settings pages, either connectr wirelessly or use the cable that came with your router to connect to your computer then go Start then Run in XP - or use the Windows key plus R in Vista and Windows 7, then type in the following into the Open box, including all the spaces:-
cmd /k ipconfig /all
then press Enter and from the black form that shows up, take a note of the numeric code beside the Default Gateway icon - something like 192.168.0.1.
Type exit to close the black form. That numeric code is what you need to enter into Internet Explorer's address bar to get to the log in page of the settings. Login is usually admin and password but your manual will help you there.