If that's the ip of your ad-hoc PC, I would put that as the default gateway in the Wii network settings. Your Wii ip needs to be something in the range 192.168.0.2 - 192.168.0.255 but be careful, because some of these ip's might be used by other equipment on your network.
Not exactly sure how you have your ad-hoc pc set up, but before you assign any ip to your Wii, use the Ping command to make sure it's not already in use.
(Start -> Run, type in CMD)
type 'ping 192.168.0.<whatever number you want the Wii ip to be>'
if you get no repsonse when all your network equipment is connected and powered up, then it's safe to assume that you can use that ip for your Wii.
Type 'exit' to close the dos box.
You might have to allow that ip in ur ad-hoc setup, depends how you have it set up.
If I were you, I'd buy a modem-router They are so much simpler, most have a decent firewall and you won't need to have your ad-hoc pc turned on in order to connect your Wii (or anything else) to the net.