idk about signal repeaters but maybe a few other tips can help
first thing to note is that wifi doesn't travel through objects well. Position your router so furniture and walls are less of an obstacle.

secondly 2.4ghz travels further than 5ghz so use that. 
The last thing I can recommend is using an app like Wifi brown townyzer to see which wifi channel is the least crowded in your area. I don't see any other helpful options in that menu.