R.M.
I know it's hard, and you want more sleep, but it's not a good idea to try to get them to drink more. Babies will eat when they are hungry and won't when they aren't. This is good if they can keep it up when they get older - as I know I don't stop when I'm full.
She's still very young and as long as she gets enough formula during the day, you might have to ride this out for a little bit. My daughter didn't sleep more than 4 hours for 4 months.
Good luck with it all!