if I say - her father left her at her two years for the time till I write it. Is it correct? or what about - her father left her in her childhood till I write it?
If I understand what you are looking for correctly, I would use something like:
"Her father has left her, since she was two years old"
or possibly (if correct):
"Her father has left her since her second birthday"
By using 'has' there is no need to use the "till I write this" bit.