Did it just start acting up one day or is this problem on a new installation?
Under your "Wireless Network Settings" configuration, I would use "802.11n and 802.11g" unless you have an old .11b device, which is unlikely.
Set your channel width to 20MHz for now; if you have competing WiFi in the area it's unlikely you're going to get a clean 2nd channel anyway.
Under "Advanced Wireless", also uncheck "Extra Wireless Protection" as that applies to .11b devices which aren't real popular anymore.
How does channel #1 look? If you have crowded airspace, you might get better results with the in-between channels such as 3-4 or 8-9. Do you have more than one WiFi device? It could be a bad router too, not ruling anything out yet.