K.
My now-18-month old son refused bottles starting at 7 months. We tried several different kinds and eventually gave up. I still went back from work to nurse him at noon, but basically we'd just send him to his sitter with a lot of food and do our best to incorporate my pumped milk into his food. We gave him a sippy cup too, which he really didn't care about too much - because I was worried that he would get dehydrated. Eventually we switched to those Nuby sippy cups and he likes them best (even now, when he infrequently takes one) - plus they don't leak, so you could put breastmilk in it for your daughter if she hasn't refused that kind yet. I know some moms like the straw cups but it took my son a long time (and a milkshake)to finially figure out how to suck from a straw - apparently this is NOT an intuitive task! Honestly, my son started using a regular cup (closely supervised) when sitting at his high chair starting around 7 months, so you may be able to put pumped milk into that too. Although if you're working from home I'm not sure that pumping is any less disruptive than just nursing the baby is.
Otherwise I don't have much advice for you except that if you've lasted 3 months you can probably hold out another 4, at which point she'll be 12 months and you can start her on cow's milk. Plus, as she continues to eat more solids you will be able to decrease the number of times that you nurse her during the day - you're through the worst part now. Be thankful that you work at home!