|If you want your DS to access the net then the only option is to reset your router security encryption to WEP on shared key sequence #1|
Your router manual will contain details on how to configure it.
You will then have to re-configure each wireless client system with the new security key. This will not affect any wired client systems.
As for long term possible consequences, WEP as a security protocol is practically useless against any savvy hacker. It can be broken in about 15 minutes. Mine was accessed in the middle of the night by a passerby who parked outside my home.
Goin' Fishin' (Some day)