It could be that your laptop's wireless adapter is not what it once was.
Try temporarily moving downstairs and test closer to the router. Move further and further away and watch the connection/performance.
Could also be a bandwidth issue. Especially if booting off other devices restores service....
As for the router, Time Warner provided it but someone there should be managing it: i.e., setting up the wireless network name, the password, the encryption etc.. If not you may have an unsecured network and your wireless bandwidth might be being used by someone else.