IMO, what was suggested to you in post# 6 may be all you need and are looking for. I have pretty much the same thing (Netgear N300 WNR 2000v5) connecting my 3 tower pcs via Ethernet cables. How fast it would transfer a puck full of information, cant say, but when I have a 6-9 unit bridge that I've finished designing, it's there in my manufacturing folder of my mill ready to go by the time I turn around and access that pc.
The dual band stuff would be more for if your running a lot of wi-fi devices, for Ethernet connections and sharing, I'm betting it will work just fine for you.
As Travis mentioned, you would still need to connect from your ISP source to your modem then to the router. In my case with my local service provider, I don't need a modem, it connects right into my router...very nice, one less chain in the link to troubleshoot should a occasional glitch or drop out occur. So far this router has been very stable.