Hi Liz,
It's great that your daughter is nursing so well. My suggestions on introducing a bottle if you need to be away from your baby - have dad or caregiver offer the bottle, when the baby is not desperately hungry. Tempting as it may be to watch and see how she is doing, leave the house. She isn't likely to take the bottle if she can see/hear/smell you, and she should associate only breastfeeding with mom.
Have dad/caregiver warm the nipple and smear some of the pumped milk on it, so your baby can smell/taste right away that she is getting what she normally eats.
If you are giving bottles to "give my breasts a break" please remember that supplementing with formula can lower your milk production - giving breasts a break isn't actually good for them, it just tells them that you need to produce less milk.
Good luck!