How to put 5ghz on my extender

Your extender only has a 2.4 ghz radio, so it's impossible to do this with your product.  There are newer extenders in Netgear's product line that are dual band. You can find them here: http://www.netgear.com/home/products/networking/wifi-range-extenders/

 

You posted this to the wrong forum area - this is for ReadyNAS, not for wifi products.  I'll move it to the correct area.