The WIFI part should really be in the center of the house. Now, you have to look at line of sight obstructions like thick walls etc. You can use a repeater to handle the dark spots. Generally the repeater needs the MAC address of the signal it's repeating. The repeater only needs a wireless connection.

In my case, I had trouble getting a decent WIFI signal sitting in a chair until I added a repeater about 3 feet from the chair. The repeater allowed coverage in the yard.