If it's seeping a little and just staining, then you can leave it for now but make sure you get it fixed soon. If its dripping, then it's on the edge of failure, you should replace it asap to prevent damage.
PS, I'm not sure about stop leak chemistry, but I doubt that it's compatble. Plus, I hate stop leak since they form little balls. In addition, on a turbo engine, a ball of stop leak getting stuck in your turbo = turbo death. Don't use it. Also, if your coolant is pink, then don't add green, blue, or orange coolant, stick with VW .