Question on upgrading pre-order

I pre-ordered the game and played my beta weekend...I want to get the Collectors addition of game...how do i go about doing that since i have already pre-ordered?

Who did you preorder from ? I had preordered thru EB games and when the Collectors Edtion info came out I emailed them and asked them to change my order and they did.

Yeahm email the dudes you pre-ordered from and ask if they'll send you a CE if you pay the difference.