Need a wireless solution for the most stable connection for gaming.

My current setup http://imgur.com/a/Fj1V5

Google Speed Test Results: http://imgur.com/a/lOS7o

Equipment: Asus RT-N66U Router Modem: Rogers SMCD3GN (Given by ISP) My PC is using a D-Link AC1200 Wireless Adapter to connect to wifi on 5.0 Ghz

I need a solution which gets me higher speeds and lower ping in my games. I'm unable to use ethernet. I still live with my parents, and my mother is not willing to have an ethernet run from the uppermost room to my room, and my father is not willing to call an electrician to drill holes in our home to get an ethernet to my room. I don't believe powerline adapters will help as my house was built before 1990, so I don't think the wiring is efficient. There is also no coaxial cable in my room.

The only thing I can think of is buying a more efficient wireless adapter that uses PCIE instead of USB.