Ubuntu Networking :: Using Workstation As Wireless AP?

I am looking to set my laptop up as a wireless AP which will allow various clients to connect to the wireless nic (wlan0), then funnel traffic to the wired nic (eth0), then on to the router, modem and Internet. I followed this guide and while I've gotten about halfway to my desired results, I've run into a wall.

I have made the changes to /etc/network/interfaces, and have successfully run the nat.sh script (or so I thought). Upon restarting my networking, the wireless AP is available, or at least appears to be. However, the laptop is unable to ping the router or Internet hosts via eth0, and when I connect to the AP, I pull a 169.x.x.x IP address, not the expected 192.168.1.xx address.

My modified /etc/network/interfaces:

Code:
# Loopback Interface
auto lo
iface lo inet loopback
#Wired Interface
auto eth0

[Code]....