Im having the same problems, if you found a solution please give me some advise,
Currently there is no such tool or functionality available within Sitefinity. I know that there are some ideas to implement this in future versions, but for now there is no such option available.
Of course with help of the API you could write your own logic to export content to e.g. XML or whatever format.
If you need any help with this, maybe I can be of service. This is something in my own interest too.