I have the router info and pass key info in the Wii, but I can't keep the connection.

Any suggestions would be greatly appreciated.

Signal strength may be too low. If you have a laptop download Netstumbler Downloads at NetStumbler.com
To access the network signal strength and s/n ratio.

You may need a repeater.

The channel you are on is too busy. Go to your router options and change the channel you are on (1-14). Test a few of them, mostly you'll be lucky and it will work fine on the 2nd or 3rd try.

PS. Check if the channel you are on is allowed in your country!