|Connect both routers by wire from LAN port to LAN port, setup a wireless network by using another SSID for the old router, switch of DHCP server on the old router.|
Connect to the old routers wireless network.
Your iBook should get ip address, subnet mask, dns server and default gateway from the new router via DHCP, and everything should work.
The original poster should always write the last response !!!
Let us know, if the problem is solved !!!