Only if the TV supports 5Ghz, if it doesn't then it would show up on the TV list of available wireless. Do you have other devices that support 5Ghz radio? If not then you can just turn the 5Ghz radio off as there is no need for it's use until you have a device that does support 5Ghz.
You'll need to consult your TVs mfr about 5Ghz support. Most devices only support 2.4Ghz.
Try single mode G or mixed G and N on 2.4Ghz?
What security mode are you using? Preferred security is WPA-Personal. WPA2/Auto TPIK and AES.
Turn off Short GI and Extra Wireless Protection if you have it. Under Advanced/Advanced Wireless.