merging 2 LANs to Internet

I have a wired router I have been using a little over 5 years now. My computers are at 192.168.100.0/24 using static IPs with the router itself at .254. My DSL service uses PPPoE.

I want to get a Nintendo DS, and that will force me to put wireless into the mix. I can't use Nintendo's own USB adapter because it is for XP only while I intend to remain with 2000 + Linux and FreeBSD. But if I could use it, it supports Bluetooth-style pairing with your DS. I have also been told a USB wireless NIC costs almost as much as a router, yet suffers from low power and greater susceptibility to interference.

I'm still rather wary of wireless, so I want to treat the wireless as more or less an untrusted network, as isolated as practicable from my existing LAN. My DSL provider won't let me have a second IP from them, or I would separate them that way. Objective 1: Existing PCs and the DS can reach the Internet. Objective 2: Anything hitting the wireless (including the DS itself) can't reach the PC's.

So here's my plan. I have tentatively picked the Buffalo WHR-HP-G54 for a wireless router. I'll connect its WAN port to one of my wired router's ports. I will then configure the wireless router's WAN to a static IP of

192.168.100.37/24 with a gateway of 192.168.100.254. If necessary, I'll make .37 the wired router's DMZ IP. The DS allows for static IPs, so I will disable the Buffalo's DHCP server and let the DS become 192.168.37.37/24 using 192.168.100.37 as its gateway. (Those 37's were specially chosen. That's "DS" on a telephone.) The DS supports "b" only (no "g"), and supports WEP only (no WPA, and they recommend 64-bit for WEP). The DS does support MAC filtering and SSID broadcast disabled.

Is the above plan sufficient to meet the stated objectives?