How To Receive The Neighbors Wifi Signal If I Buy Just A USB Wireless Adapter, Do I Need A Wireless Router To Send/receive A Signal?

If I buy just a USB wireless adapter, do I need a wireless router to send/receive a signal? - how to receive the neighbors wifi signal

I just got an iPhone, but no WiFi in my house. My neighbor has to weigh whether I should do somethings with it, you just go out and use it for a while, then re-enter. If I buy a wireless adapter and I have a wireless router, I can broadcast a wireless signal from my computer?