Sorry square, but the Westell Versalink 327W is indeed a wireless router/modem for DSL. Just a simple search for that came up with wireless written all over it.
Anyway, are you sure you entered in the 192.168.1.1 gateway correctly into the address bar? Unless your parents changed your router's gateway address, that should be how to access it. From there, unless your parents changed the password and such, username is admin and password is password.
If all else fails, ask your parents what the WEP key they created is. If they didn't make one, for one they have an unsecured wireless network and should make a key, at least, and two, you currently don't need a key to use your DS's wireless connection.