Oh, you poor thing! I think your first goal should be to keep her on breast milk if at all possible, so I have a few suggestions.
First of all, get a nipple shield. This saved the day for me when I had nipple soreness. I think you can find them at Target or BRU -- probably right next to the breast pads. You should not have to put your nipples through any more trauma!
But more importantly, get an appointment with a lactation specialist immediately! Even if you ultimately stop breast feeding, a good lactation consultant will help you with 1) healing your sore nipples; 2)successful strategies for pumping and keeping up your supply. If your insurance covers Providence, get an appointment with Dolores at the St. Vincent postpartum clinic. She is fantastic, and I am not the only mom who has said this.
Many moms successfully pump enough to never need formula, so you can try this. Unfortunately, you have to pump a lot, and very consistently, in order to keep up your supply. But it's worth trying. And at 8 months old, your daughter will naturally start eating more and needing less milk faster than you realize. By the 11th month, I was only breastfeeding my daughter 3 times a day, and at 11 1/2 months the dr. okayed me to start gradually introducing cow's milk... so you're almost there!
Good Luck!