illustrator help needed (simple thing, but i need the help fast)

i made a frontpage for a newsletter for a friends company...... now i had some objects that stretch outside the A4 i made it for...... my solution was to put a white border around it, but this gives issues with printing......

so my question is: how do i save this to a PDF that will cut off everything outside the A4 i said it should be when creating the document?

Couldnt you just transform the entire object so it fits inside?

nope........ one of the objects is a flare, which i only need part of, and cant cut.......

ow, and its illustrator CS (11.0.0) btw