Wow, this thread got buried in the flood. :(
Well, I had that router before, and from what it sounds like, you are getting an IP address automatically assigned, since you aren't doing anything special or telling the Wii to obtain a static IP address. Connecting via WEP just means that you are connected to the router but have not obtained a static IP address (which means that your Wii will always try to obtain the same IP address whenever it connects to the router).
Here's a guide that shows how to get the static IP for the Wii (2nd post in the thread):
http://www.gamespot.com/wii/action/s...=m-1-41913059&
When doing the port forwarding, you will need to access 192.168.1.1 (the password by default is "admin" without the quotes) which will bring you to a panel that looks like this:
It won't look exactly the same, but the section is still named the same. Basically you'd be following the same settings I used for IP address 192.168.1.104 (change it to whatever you assigned to the Wii).
If you have anymore questions, I can try to answer them. Hope this was clear enough.