R7800 Change Wireless Region?

Just recently bought an R7800 from amazon.com only to be disappointed with Wi-Fi range. I was told by changing the Wireless Region, the range/signal would improve drastically . Unfortunately , the option to change the region is greyed out and locked on North America. Currently the signal is comparable to my 5-year old N-router which is also a Netgear.

I moved to Saudi Arabia a few days ago and I'm hoping for a solution to this issue.