Router Control Panel Options Missing (portfowarding help)

Hi
Recently I have been trying to portfoward on one of my routers so I can set up a server for GMod (not a full time server). My router is a "Netgear DG362". Anyways I have been using a portfowarding guide on portfoward.com and I cant get to one setting on the side. When I set the router mode to "router" I can see the option called "Services" on the side under the category "Security" (services allows you to get the menu that you cna portforward in. In "router" mode I have no internet but when I change it "modem" mode where I have internet I cant see the "Security" category because it dissappears.

Any software that automatically can forward ports that is compatible with Mac would help a lot and also if anyone knows the netgear control panel and this specific problem could help.

Cheers
bs8814