Schedule, Schedule, Schedule...
If you haven't yet, read the book Baby Wise. That was the most helpful book for us. It promotes feeding scheduling. We started the method at about 3 weeks old and by 6 weeks old ours was sleeping from 9pm to 4 am. That might not seem great, but when you've been waking up every 2-3 hours, it's HUGE.
Also, if she is comfortable pumping, she can pump and have a bottle ready that you can give the baby at one of the night feeding times. Mom can get a 5-6 hour stretch of sleep, an you get a one on one feeding time. (You do have to be careful with this because some babies don't want to go back to nursing once they have had a bottle.)
Congrats on the little one and Good Luck with the sleep.