I found most of the things you ask about. Please see answers below..
Q: What Hardware version is your router? Look at sticker under router.
A: H/W = A2
Q: What Firmware version is currently loaded? Found on routers web page under status.
A: F/W = 1.02This is old FW. You could update however not sure if this would really fix the WiFi problem since there are other WiFi routers near by.
Q: What region are you located?
A: I bought the router in America. Not sure where to find "region" setting.
Q: What wireless modes are you using? Under Setup/Wireless/Manual.
A: NG only
Q: Try single mode G or N or mixed G and N?
A: I did not try changing the region
Q: Channel Width set for Auto 20/40Mhz or try 20Mhz only.
A: Auto 20/40Try setting 20Mhz only to test.
Try setting a manual channel to a open or unused channel. 1, 6 or 11. 11 for single mode N if the channel is clear.Are there any clear, open and unused channels in your area?
Q: What security mode are you using? Preferred security is WPA-Personal. WPA2/AES Only. Some WiFi
adapters don't support AES, so you might want to try TPIK only or Auto.
Q: What wireless devices do you have connected?
A: 2 iPhones, 2 Nexus 7 tablets, 1 Macbook Pro, 1 Sony windows laptop
Q: Any cordless house phones?
A: no cordless devices otherthan computers in the house.
Q: Any other WiFi routers in the area? Link> Use InSSIDer to find out. How many?
A: hghly variable between 1 and 7Having several or many other WiFi routers on 2.4Ghz can impact wireless. You could try to lower the power ouput of the 655's radio from High to Medium or Low and see if this help. I would also recommend getting a 5Ghz AP and see if this would help get away from some of the WiFi congestion on 2.4Ghz.
Q: This is probably not a FW bug as more like a external environment condition possibly.
A: Agreed, but I suspect it is the firmware's inability to deal with an environmental condition.This maybe due to the "Good Nieghbor Policy" code thats in all WiFi routers.