Babysitting in Munich

I will be spending five days in Munich with my six-year-old son in early July. I would like to hire a babysitter for a few hours here and there. I will ask my hotel if they can arrange something, but I was wondering if anyone here had recommendations. In particular, I do speak German and was wondering if someone could point me to a German version of "Sitter City," the American website to find babysitters who have had background checks. (I would need to hire someone who spoke English, though, as my son does not speak German.)