I am agreeing with the question about the distance. 125' is a 12 story building straight up. Granted, you might be going at an angle, but it seems a bit far. You might be just fine without the range booster.
I remember a guy that asked me about a similar thing a few years back, and he estimated his distance by measuring (with a tape measure) the path he took when WALKING from the computer to the router. When I told him that this is wireless and the signal goes through walls, he said that he knew that, but since he was going between floors, he had to find a way for the signal to get through the ceiling. Doh!
