Does the PC detect the USB drive if you connect it directly to the DIR while the DIR is connected to the NG router?
You have to assign a IP address to the LAN side when in AP mode as the DHCP server is shut off on the 655 and so any device connected to the 655, wired or wireless will get a IP address passed thru the 655 from the NG router. So yes, you have to static assign .201 as the APs address as it's can't get a IP from the NG router in this manor.