|Actually, you don't need a WAP.|
If you have the right antenna, you could just plug it directly into the computer inside the building with the antenna on the outside.
I would look for one that uses a network cable to connect myself, but there are plenty that use USB as well and you could always connect a couple USB cables together to ensure you have enough to reach the antenna from inside.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.