I wouldn't wake baby either, unless it is over 5 hours since your last feed,then wake bub up, change nappy have a little play first to make sure they are awake and will feed well.
I demand fed all of mine and it seemed to naturally follow a 4 hr turn around. Just a bit of trivia for you: In the first 6 weeks your body supplies enough milk to feed twins. So this is the perfect time to be expressing and storing and it will help to establish your milk supply. Don't stress he's only a week old (Congratulations by the way) he needs his sleep and so do you. If you rest well, eat healthy, drink plenty of water and feed often (4hrly as a guide, not regimented) and maintain that you shouldn't have a problem with supply.