cool, we're making progress then.
My D-link has it's config page at 192.168.0.1. I don't know wether you'll have a password set, but for mine the default was admin (the reset button will have reset the password as well).
I'm not sure how similar the different models are with respect to their setup pages. Mine is a DIR-655, as indicated at the top of it's config page.
The wireless setup can be found via the top "setup" tab, and the "wireless settings" item on the left.
mine allows for either a wizard method of setting it up, or a manual method. either should work.
While your at it I suggest switching from WEP to WPA, or if your router supports it, WPA2. This way you'll be able to use a "pre-shared key" or password/passphrase, that can be a human readable set of words rather then some random gibberish like what WEP wants.