Replacement router that does dual ban also might be an option. 5GHz is less crowded. Shorter range however and you must make sure all your equipment can use 5ghz band.
I was figuring I would have to migrate some of my hardware over to 5. Laptop didn't get a good signal in bedroom. I am in very crowded 2.4 area. Replaced my dlink 655 with Asus ac-68 laptop has no trouble connecting to it now. Now my hardware is split between 2.4 and 5.
Another option I have very good results with are Homeplug »
www.amazon.com/NETGEAR-P ··· homeplugOnly tested netflix streaming for short time with them but it worked perfectly. From other reviews these things either work perfectly or are useless.