Received Warning ID NON-2015-0211 on Netgear Router WNR2000v4 - Need Help!

I scanned my home network using Avast, and it came back with a warning that my Netgear Router is vulnerable to hacker attacks.  I'm not terribly savvy with routers and the like, but I'm very concerned over the fact that my home network is vulnerable!!  Avast did tell me that an update of the router's software/firmware might solve the problem, and from there I found my way to the Netgear Community.  Could someone explain to me how I do this and where I find the update, please?  I really need some help.  Thanks.