I'm glad to hear they're getting better. I'm not sure what happened early to get them in that state, but that much damage suggests something went very wrong for you, that's for sure. It most likely wasn't your breasts that were the problem, though, but perhaps the help you got early on.
You are doing a wonderful job feeding your baby under very difficult circumstances - well done!

As for exact amounts to express, I don't know. Have you tried giving the ABA helpline a call? They may be able to give you more specific guidance on this. 1800-686-268. I would just think, as a general guideline, to try and get your supply up to where it will need to be in a few weeks time, so a bit more than what she is taking now. We know from research that individual healthy babies take anywhere from 500-1200mL per day, so it varies a great deal baby to baby. With a bit of time I guess you'll find out how much your baby needs. Also remember that it's normal for babies to take different volumes of milk at different times of day - sometimes bigger amounts, sometimes smaller - so maybe think about the total amount you pump in 24 hours, rather than the amount per feed. If you're getting a bit less overall, then you could introduce an extra pumping session, for example.

Hope the nipples are in tip-top shape very soon.