Best thing is to keep her upright as much as possible. You can also try elevating one end of the cot/bassinet or wherever she's sleeping.
DS had silent reflux which was quite bad from roughly 3-9 weeks and then gradually improved. I slept sitting up in bed holding him upright for several weeks as it was the only way he'd settle - he was so uncomfortable when lying down.
Hopefully it'll sort itself out in the next couple of months