Nintendo DS Wifi

I currently have a computer connected by wireless WPA2 connection to a router. I want to connect my DS to the Internet, but it can only use WEP. I have tried using my computer to connect ad-hoc to the DS but the computer just disconnects from the router. I cannot change the router's type to WEP.

Also, I have a HTC Hero on Sprint, but root access hasn't been gained to this phone on Sprint so I cannot use Android Wifi Tether for a wireless ad-hoc connection.

The fundamental goal is just to convert signal to WEP and still maintain wireless connection to the router for the device providing the second-hand connection (computer or phone in this case).

Is my only option to have my computer wired and use an ad-hoc connection? I'm going to try that soon. Please post suggestions.