Connecting to a secure wireless network, help (legit)

I'm at my grandparents house trying to connect my laptop (running XP) to their secured wireless network. The problem is, my uncle set up their internet because they don't know anything about computers (they didn't even know that they we're using wireless), and my uncle is unreachable.

So, their computer is running Windows 98, and they connect to the network by a Wanadoo service program. (Just to add a little confusion, everything is in French, and I'm not quite fluent but close) Inside the program under the configuration menu, the following information is listed:

Identifiant de connexion (Litterally connection ID, but I think it may be the Network Key)

Mot de pas de conexion (the password of the connection)

And then some other menus that I think may be irrelevant...

Well I tried entering the "Identifiant de connexion" for the network key, but that didn't work.

So, please, any help would be greatly appreciated. I've heard of ways to get through this kind of thing, like setting up remote access and whatnot, but I'm not too familiar with it, especially on Windows 98.

-Thanks