I'm not sure of your feeding routine, but when my son started sleeping through at 6 weeks, he would sometimes sleep past the 9 or 10 o'clock feed and I was so worried he would wake up during the night, I made noises and bumped the cradle, etc so he would wake up and then I would give him his last feed. Sometimes it may have only been a top up but it got him all the way through until 8 or 9 in the morning. Now it is a pretty solid routine. He just wakes up for the last feed and then sleeps through. 12 hours is a long time for them to sleep but 10 is really good. Just enough time for me to sleep too. We also found that keeping him awake for a couple of hours between the 5 or 6 o'clock feed and the 9 or 10 o'clock feed helped him settle down quickly after that last bottle and he wasn't wide awake and wanting to play. He will just put himself to sleep when he is ready, but quicker rather than later.
Maybe another idea could be to introduce some solids around dinner time and the extra solids in her belly will help her to sleep longer too. She won't get hungry quite so quickly.
Anyway, good luck. It worked for us. It worked a charm actually and very quickly and easy one to do. No pain involved in this routine.