galaxy note 2 extended battery cover and docking station...

I was wondering where to find the aftermarket battery cases that look like phone back covers as well as the docking station for the note 2 (GT-N7100) bought recently in thailand.

- Are there particular brand names that are better than others?

- prefer some grip [on the cover] (rubber or other groves). The note 2 is large and

- how much extra power would I get.

- for the battery, will it require that the original back cover be removed?

- price?

Chumphon is limited to local shops, tesco, big c, banana IT, Jay-mart, telewiz/dtac stores. I can go to bangkok or order from an online shop if there is good recommendation.

The dock I only have a mild interest in, but figured I might get some other experience with it also.

edit: the battery does not have to be built into the cover. It can be separate, which might be a good thing. But I was hoping for being able to use the original battery AND the extended battery together in parallel (or series).