Kept in the fridge it is fine up to 8 days (4C or lower, keep in back where temp is more stable).
If it's something you seriously want to do, then I'd rent a hospital grade pump. Check out the NCT website, since yours is quite young, you'll probably get some help in hiring it, otherwise it's about 30pounds a month (well worth for multiple expressing)
Amounts. I don't know newborns but from 6 weeks, typically 24oz a day (19-25oz) before this, they gradually work up to it.
They tend to take more from a bottle rather than the breast directly.
You will need to express in the middle of the night and ideally at least 8 times in 24hrs. You'll need to watch out that you don't produce an oversupply, so make sure you don't build up to getting excessive amounts out. By no means is expressing an end to breast milk, but formula tops-up make it more likely.
Can you hire a lactation consultant to come round?
You can look up cup feeding as a way of feeding her (google dr jack newman, he has a video on his site). Let her latch onto your good breast as much as you feel comfortable with.
None of this is permanent, give yourself a few days, get better and then reassess.
I would get as much RL support as you can, if that means seeing several different breast support people then so be it. At this stage you probably need/could do with emotional support as well as practical help.
And most importantly, you are not bad or failing mother. You have gone above and beyond what most people will do to keep BF. At the end of the day, if you're ill and depressed then the effects of BF will be outweighed IMO. To fully express is the considered the hardest of all worlds, so you are not copping out, you're proving how far your willing to go to even attempt it.
I hope you get some more RL help and that things improve for you