Hi Necla,
Judging for your plans, I do think that the JR Pass could be a good help in making savings over normal tickets.
This because the 7 JR Pass is just about the same price as a normal return between Tokyo - Kyoto on with the Nozomi express. In addition you get 7 days of unlimited travel which makes for a pretty good deal. For instance you can use it on the local JR network in Tokyo and to travel to Narita Airport.
I have to say that you can't use the Nozomi Shinkansen, however you can take the Hikari Super Express instead. This train is exactly the same as a Nozomi but makes a couple more stops on the way. The end result is that travel to Kyoto takes 19 to 20 minutes longer.
I hope this helps and have a pleasant trip!
Daniel