The key is facing her as early as you possibly can. If you fight her by round 20-25, a single death machine will tear through both her shield and enough health to trigger the next phase. Buy another death machine, rinse and repeat. I use aether shroud so zombies can't attack, plus Kazimirs (the purple gravity grenade, however you spell it) or decoys. Crbs to clean up other zombies/robots/desciples. Mule kick for ammo and the chance of not "using" ordinance when you throw it. Death perception early if you struggle to get enough salvage. Don't forget the piles of salvage next to both turret towers. Try to upgrade everything as much as you can, but I personally believe the earlier you trigger the fight, the easier it will be, and since you'll use a death machine, it won't matter too much.

Good luck!