Media for Which Antenna should I buy ??

Which Antenna should I buy ??

I have a situation where I want to increase the signal of a wireless router to another building.

They are both two story buildings on a campus. Wall ---- To Wall 125 feet. I think I would put the broadcasting antenna on the second story of the first building. The building I want to broadcast to is a about

100 feet long 50 feet deep. The signal will be hitting the longest part of the building. In other words imagine that building is a rectangle, the signal as I imagine it will be broadcast to the long part of rectangle/building, so the whole building. This wall is made of brick and has several windows in it. (its a residence)

I have been looking at a couple of Antennas. Unfortunetely when I call the companies they are not all that helpfull on what I need. Im hoping you all can give me some help.

Here are a few Antennas I have found.

Hawking tech HSB2 Specs (im not sure what it all means but I will put down some of what they feature) Gain: Up to 27 dBm Output 100/200/500mW (seems that you can adjust it) Input power 8dBm min; 18dBm max Receiver Gain 10-13dBm, 12 dBm Typical (I think? i just attche it to my existing router by removing an antnenna)

Hawking tech HAO14SDP

14dBi outdoor directional antenna (they say this can go 2 miles. This is really too much for me. Im not trying to broadcast NBC, but they have a huge selection of products and I really dont know which would be right)

USROBOTICS USR5482A Outdoor antenna Gain 9dBi (they also have a 14dBi

Has anyone had any expereince in this and can they provide me with what might be right in my situation.

Thanks.