I'd say give it a go, but definately consider renting, you may be able to get a "big German style house" here but you're looking at the wrong country for an American style place

as I said in the other related thread look a bit outside the towns in the surrounding villages for a cheaper place. Cant help you with schools etc no experience of them in this area but as some have already stated dont expect to be overwhelmed by the standards here.
As for weather looking out of the window now it's terrible but dont take that to heart it's ok as a rule, great cycling country too (ie flat) which is good as I've started cycling the 25km to work now. Still if you get here give me a shout always room for a few more at our BBQs

ETA: Forgot to say Celle is perfectly situated to get to the cities of Hannover, Hamburg and Bremen so you wont be missing out by being in the sticks too much.