Couple things to try..
1) Try connecting to a friends Wifi or to your phones hotspot and see if the issue still crops up.
2) This is a bit extreme but maybe unscrew the back speaker cover and be sure all the Wifi antennas are connected properly and not damaged (this will not void your warranty)
NOTE: the drives on Asus's site are not up to date. Try going to this site and see what it says about your wifi drivers (assuming you have an intel card that came with the stock G46Vw
http://www.intel.com/p/en_US/support/detect
G46VW (Now with THUNDERBOLT!!), 3840QM (overclocked, cTDP, 72w), Modded BIOS, 16GB, Samsung 750GB SSD, 1TB (Samsung mSATA) Liquid metal thermal paste