I would run chkdsk periodically to make sure that this doesn't degrade further, but a few damaged sectors here and there is normal and nothing to be particularly worried about. During normal operation, a hard disk will (transparently to the operating system) re-map any damaged areas to non-damaged areas, and report that in the SMART data.
Which brings me to the next point, that you may want to download and install (if you don't have already) a utility which will allow you to inspect the SMART data from the drive. I'm not too sure what's available in Windows to do so or if it'll work over a USB connection, but that will tell you if the drive is remapping large amounts of space or only a few odd blocks here and there. If it is remapping a lot of space, then you should consider replacing the drive as soon as reasonably possible to avoid the risk of data loss.
The drive can transparently remap only a given amount of data, and when it runs out, then data errors are going to start trickling through to the OS. Which is why you want to keep an eye on any damaged blocks count reported by the OS utilities. If that number increases by any significant degree, that is a good indication that the drive is about to fail.