So I notice Amy isn't mentioned in that announcement, I assume something happens to her at the end of the series, and as she's apparently confirmed for the Xmas Special and the 2011 series I reckon the Xmas Special might involve The Doctor rescuing her?

Maybe the Doctor and Amy get temporarily separated sometime (Amy's Choice"? perhaps), and this is what the Doctor does in the meantime?

Rose wasn't in 'Attack of the Graske' because she was at an Abba concert.

Maybe she's off on a real honeymoon with Rory. I really wouldn't worry too much about it in terms of meaning much for Amy's character.

I read of a quote from an interview with SM (quoted here, I recall) that RTD had asked to see one episode of the new series for reasons that, at the time, SM was not prepared to reveal. Maybe this was the reason.