Have you checked the printer documentation, is it capable of connecting to a wireless network that is using WPA_2?
Is there a means by which you can print a configuration page that will show the IP address of the wireless interface for the printer? Usually this involves holding down a button when you turn the computer on, again the printer documentation might help with this.
I know in a lot of instances with these type of printers you have to choose a single connection interface, sometimes they will not support both wired and wireless simultaneously.
Is the Netgear router the only source of wireless DHCP on your network or is it possible the ATT device may also be handing out DHCP address, not exactly sure why you are employing double natting with a Class A and a Class C private reserved IP addressing scheme. It just seems to me that things might be easier if all network devices were on the same subnet.