Are you German, do you live in Germany, do you speak/read German and can follow the news? If yes to any of those, I will listen to what you say. If not, then, well, you are welcome to your opinion. While I don't outright dismiss it, austerity is not high on my list of guesses on Germany's economic situation. And let's be honest, we're all guessing.
No, Germany is doing well because of all the exports to China.
Note: I speak and read German. I've had this conversation with German friends of mine who currently live in Germany so I dont' feel I'm completely the economic equivalent of a 72 hour journalist. (A 72 hr journalist is someone who goes somewhere for 3 days and thinks he understands everything about the place. )
I would not put 'austerity' and 'China' in the same sentence. The Chinese government is spending money like a sailor on a 3 day leave at port. The amount of money their spending on infrastructure along is embarrassing. Highways, bridges, dams, ...
Also, China's move to a market economy can be more aptly described as 'Ooooh, capitalism brings in lots of cash. Let's do that but with 'Chinese characteristics' (read: capitalistic but not democratic.)
Also note: I speak and read Chinese as well and lived there. I've also had this conversation with Chinese people in China.