By default the power TRANSMISSION is set to 100mW but can be dropped down to 10mW to conserve power. I personally drop mine down to 10mW since I am really not too far from my router and it really saves on the power usage.

You can find it here:
Control Panel -> Connectivity -> Connections -> (edit any existing connection) -> Next -> Next -> Advanced -> Other -> WLAN Tranmission Power

But, you were asking about reception rather than transmission. Both are still important since you have to have enough transmission to send handshaking/data back and forth.

I personally have done the parabolic idea with success. The only problem is trying to hold a metal bowl while working with your NIT. Plus, it looks goofy and suspicious.


Ooops: Eiffel beat me by three minutes. Sorry for the double answer then.