Imposition layout problem?

Please help,

there is probably and easy solution to this but can't seem to find it.
When I go into print preview and imposition layout the tile/block (or how do you call it-selection box) that you rearrange is actually my whole page, not my design size. That means I can't put any more of them in the same print without scaling them which is not an option.

While I'm here - and what is the best way to send a file to the press (some other company) with print merge and imposition layout already arranged as I have custom fonts and stuff they would not be able to change in merging by them self?


Thanks