Hi M.,
My daughter NEVER drank from a bottle, so it was pretty tough getting away... so I feel your pain :) As such the only way I was able to get away at all was to slowly increase the time in between her feedings, because like you, I was feeding on demand which is often done more for comfort purposes for the baby than for nutritional purposes. So, as one of the other mothers suggested, I would try spacing out your feedings a bit more so that you will end up in a position where you can feed before the ceremony, after the ceremony/before the reception, and possibly after the reception without her fussing for her next feeding in between, therefore eliminating the need for a bottle altogether.
Another possibility involves switching from trying to get your baby to take a bottle, to trying a sippy instead. We actually introduced our daughter to a sippy around 7/8 months because she absolutely refused a bottle, and she did start drinking a bit from there, fortunately. And, again as another mother also suggested, the baby is less likely to take anything other than the breast from you because why would your babe want a sterile bottle/sippy when they can have a nice snuggly, warm breast? Perhaps her father or another family member can begin introducing her to another form of feeding, i.e., bottle or sippy.
Babies get into routines and a comfort zone, so naturally they are not inclined to change overnight- but with patience, love, and a little flexibility it should all work out in time for you to enjoy yourself at the wedding!! :-)
Best of luck,
L.