You CAN have her sleep through the night and still breastfeed. Babies don't live perilously one feeding to the next. If you force her to go without the breast at night (gradually cutting down one feeding), she WILL learn to eat more during the day. I promise.
The only slightly challenging (uh, "slightly" is an understatement) is that the last thing most people want to do when they're dead tired in the MOTN is rock a crying hungry baby back to sleep. It's so much easier to bring the baby into your bed and nurse you both back to sleep.
It's your choice though. If it were me, I'd have to choose a painful few weeks of night weaning but continuing to breastfeed full time. Even if you add a bottle during the day, one could never predict the outcome. It could end up that you're still nursing her at night anyway, but your breastmilk just dries up during the day.
The other thing I've found, at least with my kids, was that they're so active during the day they had a hard time settling to nurse. Therefore, at night, when everything is quiet, they nursed much better and my supply would gradually adjust to increase in the MOTN because they were doing their longer, more intense nursing sessions then (and much shorter, more frequent sessions during the day). You can reverse that. It just takes stubborn persistence. If you can get backup from your SO that would definitely help you out.
Some people don't mind CIO, and that works as well. Personally, I think letting a baby cry for a few nights, but extending nursing (and your sanity), would be worth it. But then again, many people wouldn't agree with me. We ended up letting my ds CIO at 12 months. Once he started getting a full night's sleep he was a completely different child... much more pleasant to be around. I felt like I was a much better mother too, because I actually had the energy to DO things with him. I think the lack of sleep was getting me depressed too, which is never a good thing.
I'm lucky my dd has been a bit of an easier night timer than he was. Or maybe it's because mommy's a little more stubborn and not giving the boob at the first peep this time
Just my two cents