I think fruitscone if you speak German to your dh at home and you live in Germany, it will be difficult to maintain her English. German will become her dominant language unless you choose an English language nursery, schooling and once she notices you understand German (via your conversation with dh etc), she will not be highly motivated to progress with English. It can be quite an uphill struggle.
Whereabouts are you in Germany? Do you have bilingual schools there?
I personally, reflecting back on the mistakes I have made, would consider sending her to a purely English language nursery if you can so she is really well based in Englsh before she starts school. German she will pick up naturally from her father, his family and the general environment.