Glad you got it working. Manual here http://www.downloads.netgear.com/files/GDC/DGND3700V2/DGND3700v2_UM_05June2014.pdf
Edit: Have a look here for HG612 stuff
As long as you are changing your computer IP address to the same subnet when you plug it in to the modem you should be ok. Have you unlocked the modem as per the instructions in the link?
Ah, ok, thought you needed to unlock it. Are you trying to see the stats with your PC plugged into LAN2 port of the modem or your router? If you are connecting via your router, you will need to connect LAN2 port of the modem to a LAN port on your router (as shown in the kitz document). You will also have to change either the IP address of your router to 192.168.1.x or change the IP address of the modem to 192.168.0.x
You will need to refer to the router manual to change the IP address. This will have implications on the rest of your network. If every device is set up for DHCP there shouldn't be a problem. If you have any static addresses set, you will need to change them to the new subnet. If the device you are using to change the IP on the router is configured with a static address, you will cut off the branch you are sitting on, so to speak, and will have to change it to the new subnet before you can re-connect to the router.