@ 11 - Ah, that sounds very like the experience of some fellow foreigners I knew when I lived in Germany. You have to be a fairly advanced speaker to get people over the well-meaning but sometimes intrusive "but I will practice my English on you!" stage, and then the question is how on earth you're supposed to get there if everyone from train conductors to the ice cream man keeps interrupting you and trying, so very helpfully, to speak English. A grad student I once knew was completely maddened by this -- because, uh, she was studying German. And did a fine job of speaking it, too, except that she had a clear accent.
That said, I don't think you need to go all that far off the beaten path to get away from that tendency, at least if you're making a good-faith effort to get people to actually speak to you and not traveling around with a gaggle of other English speakers. Sure, you can pretty much give up on the touristy areas and the big museums, but you can find art exhibits, readings, and all manner of other activities in any big city, and certainly any university town. They might not be the most scintillating thing you'll ever do, but they're great for learning. Second-string tourist attractions and small or budget hotels are also great in this regard.
In short: It takes work, but it's not impossible! Just keep banging away at it, and before you know it, all your conversations will start with the other person's amazement at how well you speak German, questions about whether your parents were German, and so on. Boring, but flattering. ;-)
Oh, and no need to be self-conscious about saying "zwo" on the phone for addresses or phone numbers. It's really pretty handy.