What you need to do is open the properties of the device in question. and click on the Details tab. It will display a string such as the following:
PCI\VEN_11AB&DEV_4320&SUBSYS_0CC5105B&REV_14
What you need is the Vendor and Device code. For example, the Vender is 11AB and the device is 4320.
Next you need to goto to
http://www.pcidatabase.com/index.php to search for your device.
Alternatively, if the above is too complex. Try a Device Scanner such as the one provided at
http://www.driverguide.com.