As for the one basic question that no one bothered to answer yet: Yes, they're dubbed. Basically every remotely costly series or movie from America comes with a dub. Your only issue is to find them. I might actually recommend that you watch dubs instead of German productions in the beginning because voice actors speak more clearly and with less of a regional accent, all of which comes into play whenever actors are involved (goes for all languages that I know so far, btw). Since you know the series already, you can also consider what kind of sentences, speed or words you'll come across. Other than the usual buy to use services, netflix, amazon and so on, I cannot provide you with a legal link :) Sorry. Some of the television stations offer parts of their program on demand for a couple of days after it was sent. But really just parts, and very rarely the good things. Though the ARD at least includes the movies they produced themselves (also just for a while after it was sent), but that defiles the dub idea.

If you have a netflix account, they have some shows that you can switch to them speaking German and or CC in German.

serienjunkies.org - not all programs are with subtitle but a lot (depending on uploader). For example "Games of Thrones" season 6: http://serienjunkies.org/serie/game-of-thrones/

http://www.tvnow.de/ has quite a few, though usually only the latest broadcast episodes are available for free.