I bought a b3 yesterday and I haven't been able to fiddle with it eough yet

However my main weakness lies in network configurations, how would you set it up to run having my set-up. My internet provider is Comhem (cable) and I also have tv-services from them that requires internet connection.
My current setup: internet -> netgear-gw/router -> LAN [B3 connected via it's LAN port to a LAN port of the router]
I can reach it using it's internal ip, but I can't seem to reach it from outside [should I put it as a DMZ device in my router?]
I know using nslookup that the outside address is my gw/router's IP adress, so I guess it blocks the traffic to B3.
Any advice would be greatly appreciated