You just mentioned the reason why I am saying in the end you will want to buy a proper audio interface. You will have system latency using generic drivers. You see once you get going what I'm talking about. 
With windows and Sonar it works best with well written ASIO drivers. All else will perform poorly. Timing issues , out of sync tracks and latency are a few of the issues you will experience until you purchase a audio interface with good drivers. 
You don't have to take my word but I am sincerly trying to help you have a better experiance with your new hobby. That cable was just a sad waste of money.