On the Select Network Adapter1 screen, click the Have Disk... button.
Note: You don't need to select a Network Adapter here. The zero, one, or more entries in that box don't directly represent the actual device(s) you have installed but instead represent the available drivers that Windows 7 has for this particular piece of hardware. By clicking Have Disk... you're skipping this existing driver selection process and telling Windows 7 that you have better drivers you'd like to install that it isn't yet aware of.
 The name of this screen will be different depending on the kind of hardware you're updating the drivers for. A more generic Select the device driver you want to install for this hardware is common.