Given our experience (I couldn't manage to sterilise-pump-bottlefeed every day, it was just too much. DS ended up refusing a bottle), if I could go back I would have given him one bottle of formula a day. Many people feel very strongly about continuing to breastfeed exclusively, so it's not for everyone, but it would have helped me immensely to know that I could be away from him occasionally. I felt trapped by the exclusive feeding in the end.
So if you're open to it and you really want her to take the bottle, it might be worth considering formula once a day.