I ever wrote a tutorial at http://www.systutorials.com/136003/iphone-connecting-internet-using-windows-pc-network-through-usb-cable/ . But please be aware that it worked only on specific OS combinations.
So, I am not sure whether it can work for Windows 8 + iPhone4S (it also has several versions of iOSes too).
The easier way may be just to set up a WiFi hotspot in your Windows 8 possibility with the help of a WiFi adapter. A basic one could be less than $10 on Amazon.