|just an added note, you do not need to reboot the modem if its just the wireless having issues.|
Next time you lose the wireless connection check the wireless icon to make sure its still connected to your network.
case in point, my wife was complaining about our home wireless network being slow. I checked everything and it was fine. Lo and behold when I checked her laptop she was connected to a open neighbors wireless network. I changes a few settings on her laptops nic and all is well.