First, as others have said, 2 months is really, really early, and her skull is still very 'plastic'.
It/s worth checking there isn't an underlying physical issue (my dd had torticollis, and associated head flatness, as she always slept with her head on one side - it was uncomfy for her to move her head to the other side) - so check if she turns her head freely and equally to both sides (eg will she follow a toy all the way round?
Think about what might make her always sleep on one side in the cot (toy/light source?) and consider moving the cot around/twisting it to overcome any of these
Lots of tummy time to strengthen muscles, and certainly look at pillows (we also used a rolled sheet under her to slightly tilt her the other way, but iirc, SIDS advice was against that)
As well as watching the amount of time she spends in any 'head rubbing' situation (bouncy chair/cot/buggy etc) - as others have said, slings are a fab option.
In terms of the corrective helmets - I would say you have LOTS of time to improve the situation on your own before you need to worry about those (only available privately, so an expensive option)