@alwaysneedhelp 

You could try a Range Extender but know that extenders do not provide better speed and in fact in most cases they provide lower speeds than the router does.  RE are just to expand the range.  I'd recommend the RE505X. 

You can also look at Powerline adapter which are wired or wireless APs depending on which model you get.  They typically provide better speeds and range but depends on the quality of the powerline in your home and all adapters have to be on circuits fed into the same panel.  I recommend the TL-WPA8630 Kit.

Lastly you can look at replacing the router with a Mesh system like the Deco X20.  With mesh if you need more coverage you just add more nodes,  up to 10 per network.  the Deco X20 is a good choice.

Also look at your ISPs gateway.  Part of the problem could be that its creating interference.  I would recommend disabling its router and wireless functions as having two routers and two wireless network devices in the same enviroment can create problems including wireless interference.