The Winter War — Niall Teasdale

The Jenlay, Herosians, and Torem have lived in peace for almost five hundred and thirty years. The Lorenti Federation was founded specifically to stop anything like the Xinti War happening again and, through all that time, a woman named Winter has sat at the top of the Federal Security Agency ensuring that the peace is kept.
Long before even the Xinti War, Aneka Jansen was torn from her home on Earth and converted from a flesh-and-blood woman to a robotic version of herself. Then she was trapped in deep space for a thousand years, waking up to find the world she knew was long dead, and her new home was New Earth.
Now forces are at work which could tear the Federation apart, and Aneka and Winter are at the centre of their plans. Neither woman is what she seems and now their secrets could mean the end for everyone.