that work with Windows 7. Probably it depends on the product in question if the driver already is present or comes with it on CD or downloadable. When it doubt: ask the sales person in the shop.

An alternative for a USB adapter is an Ethernet adapter. Gnerally, those come with an antenna that you can position on a place that has a better reception than where the USB thing on your PC is. So I would prefer such a one. And probably it's plug and play without any driver needed.
Here's an example: