Q: Wifi Dead Spots in House

I have a mid sized house and I'm using AT&T wireless router (brand new from AT&T).

I have a couple dead spots in the house where neither any phone nor macbook nor any device can hold on to the signal.

Its RIGHT where my couch is where I like to watch TV.

ANY suggestions as to how to increase the signal?  i can't move my router because the 'homerun' (where ALL my home network cables lead to) is in my closet hardwired.

Are there any boosters or extenders that would allow me to extend the current network to fill the entire house?

THANKS in advance!