There are few factors in "Depressed" WIFI service at home.
1. "Lousy" choice of current Router.
2. Good Choice of Router but "lousy" specific unit.
3. Wireless clients with "lousy" Client Wireless cards.
3. Environment full of electrical noise an obstructions.
4. Unrealistic Users expectation based on wishful think and ignorance.
1. Get the best Router with a potential to work well.
Currently it is probably this one - Asus RT-N66U -RT-N66U
2. Use a good laptop with very good Wireless card to survey and evaluate the environment.
Usually a Brand name ABGN modern card would do (if you are not sure use Apple MacBook).
3. Play around with positioning of the Wireless Router in the environment while using the Laptop running a program like this, http://www.nirsoft.net/utils/wireless_network_view.html
4. If none of the above help than you need to lay additional Cat6 cable and add Wireless Routers configured as an Access Point. http://www.ezlan.net/router_AP.html
Most important is to understand that if One faces, I can not move the Router, I can not add even one cable, ans similar restrictions. Then Up in the sky it was probably marked as One fate against One having a good WIFI service. One can keep complaining because it good for the soul, but the WIFI will sill be bad.