If you need to reset the FireBox (and I think you will), unplug the device, hold down the reset button on the back, reconnect the power, but continue to hold down the reset button until the yellow Attn light stays on. Dauman is right about the switch, it is unmanaged.
You can use tracert to find your gateway. Just run "tracert google.com" at the command prompt and the last address before going to a public address should be your internal firewall address. Chances are, it may not matter because you might need to reset the firewall box. Good luck!