|As with all drivers, you go to the manufacturer's website to get them if they aren't supplied with the device. If that proves difficult because the brand name and model are not well-known, you should in future buy a well-known brand which has excellent website support.|
For webcams that means Logitech, Creative, or Microsoft. Okay they usually cost more money than an obscure brand, but you won't have any problem getting drivers for them.
It's pointless buying cheap stuff to save money if you can't get it to work for want of a driver.