Both can be taken together as they work on different parts of the brain.
Valium is addictive but not if used occasionally. But Dr's prescribe it for 2 weeks initially as this is the optimum time of useage.
Zopliclone is not SUPPOSED to be addictive as such BUT you can become dependent on it over time. Again a 2 week prescription is the optimum time.
If your Doc has given them to you to get over a difficult time in your life then use them as prescribed.