Are you saying when the connection is dropped, it's the internet you loose, you can still browse to the router's admin pages, or are you unable to even see the admin page
If the internet connection is beinng dropped, that would be between the router and modem. to fix that you'd normally need to reboot the router and / or modem.
If you are just rebooting the PC it suggests the problem is either on your PC's configuration or the router.
Have you checked for any updated firmware for the router? Are all your drivers on the computer current? Do you you have anything running on the computer such as torrents (p2p)? Do you see similar issues if you connect wired rather than wireless?