You say a router would be overkill, but how good is the router/firewall functionality on that Netgear combo box? One option might be to just let it be a modem, turn off all the firewall/routing stuff, and bridge it to a better router. I'm pleased with my Linksys WRT610N running TomatoUSB, which now supports simultaneous dual-band wifi. Keeping my 802.11g peanut butter and 802.11n chocolate on separate bands has made things a lot smoother, and the TomatoUSB firmware has a lot of goodies that your Netgear probably doesn't have (my assumption is you can't flash a combo box like that with aftermarket firmware since it's got the modem on it.)