"I am truly lost and have no idea what to do."
It's quite likely that your poor performance issues are being caused by nearby wireless interference. That interference could perhaps come from a neighbour's wireless router that's using the same wireless channel number as your Netgear. If they turn their router off at night then that may account for your symptoms.
"........ bought a Netgear WNDR3700 Dual Band Cable Router thinking the signal would be better."
If your wireless devices support 5GHz then the easiest thing to do is to set them to connect using that rather than the crowded 2.4GHz band which is prone to interference.
Alternativley, log into your Netgear and change its wireless channel number. Experiment with channels 1, 6, and 11. Don't forget to save the settings each time.