The following answer answers nicely how to use multiple APs for a single wireless network
The answer states that your device will change to a better AP if the connection drops below a certain level and a better AP is available. But, as pointed out in the comments, computers tend only to change AP when the connection to the current AP is extremely low. Basically, it hangs on too long.
Is there anyway to increase the threshould that your computer swaps APs?
I finally have good coverage in all points of my house by using 4 APs but still have connection issues as my computer stays connected to a far-away AP.