The Terran Privateer — Glynn Stewart

Earth is conquered.
Sol is lost.
One ship is tasked to free them.
One Captain to save them all.

When an alien armada destroys the United Earth Space Force and takes control of the human homeworld, newly reinstated Captain Annette Bond must take her experimental hyperspace cruiser Tornado into exile as Terra's only interstellar privateer.
She has inferior technology, crude maps and no concept of her enemy, but the seedy underbelly of galactic society welcomes her so long as she has prizes to sell and money to spend.
But when your only allies are pirates and slavers, things are never as they seem -- and if you become all that you were sworn to destroy, what are you fighting for?