Try to give your baby all the food she needs during the day, as long as she gets all the nutrients needed, she should be able to sleep well during the day (... this is according to Gina Ford's book ... as said in other threads... and that's my belief too). It works for me... and it works for many many Gina Ford babies... so try it.
FYI... my son has been slept thru for many months already. He sleeps at around 7.30pm until around 6am and he normally won't wake up in between. I feed him 1 rice cereal and 2 congees and a total of about 18-20 oz milk to him during his awake time and he's contend.