|A Wireless Access Point isn't going to help much. A Wireless Access Point is just a standalone version of what is already in the router. |
This is the thing about quoted figures. They are the best that can be achieved under ideal conditions. Where radio signals are concerned, ideal conditions very rarely exist. This includes direct line of sight with absolutely nothing in the way. As soon as you put something in the way, like a brick wall, the signal drops of dramatically.
What you can try is repositioning the router and repeater slightly. A difference of a few feet can sometime make a dramatic difference as well as swivelling the antennas so that the are parallel to each other to get the maximum signal strength.