If it is wireless exclusively that is shutting off, then it could be something simple like a Wireless channel that has a lot of interference, and you can change and fix that by going into the router. eless signal.
Open a browser, and go to http://192.168.1.1
user name is admin. and the password is most likely the serial number found on the service tag of your VZ router unless you changed it. Once you login succesfully, go to the top and hit wireless, then on the left basic security. then go to option 3 which is channel 1, 6 and 11 and are the only channels you should try.
So it will likely be set to auto, change it to 11 and put the check for keep settings even after reboot (Directly under the channel) and then hit apply. after you hit apply, test your connection out, if you notice a difference, leave it like that until the problem happens again, and if it happens again, go back into the router, and try channel 6, test it out. and then finally 1 if the first two don't work.
Also take a look at page 2 of Actiontec's Wireless PDF File. It gives you some idea's with regards to position and orientation of where the router sits and how it can best be positioned for maximum coverage.