Berlin advice

I'd recommend attending courses at the Goethe Institute in London first before you make a move. It'll give you more confidence and a feel for German. Their courses are supposed to be very good (although I've obviously never done one there).

I did a week intensiv course at the Goethe Institute in Berlin, it was really well done but pretty expensive,
I switched to the Hartknackschule and did their 6 month class, it was a lot cheaper and really helped, the teachers would help with all kinds of random stuff aswell, setting up the internet, translating etc