There is no end date set for Vista support as we speak: http://support.microsoft.com/lifecycle/?p1=14118
There are no plans to discontinue support for Vista for CIS as known right now. Not even for the older XP. Notice that Vista and Win 7 share the same driver foundation (read they are very very similar) and that Win 8 will be building further on the foundation of Win 7. I ran CIS on Win 7 beta where it was not even ready for Win 7. That's how similar they are.
In short. You can keep on using CIS under Vista for a long time.