The first step you can always take is contacting the person who reuploaded your video. Considering Pewdiepie's demographic it is very possible that this is a 12 year old kid who doesn't realize the impact of his actions. Try not too get upset or emotional in your message. Contact him as 'the original creator of so-and-so video' and let him know how much time and effort you have put into this video. Mention that it is not okay to download someones video, slap some subtitles on it and upload it as your own. Say that you will have to take official action through Youtube if he does not delete the video. This on itself might already be enough to scare him into deleting it.
On the other hand, if contacting him/her doesn't give any results, you can report the video. Click report -> Infringes my right -> Infringes my copyright. You can also do what Steve says, but small channels do not have this options.
