After barely defeating Lawrence Barrett I had resolved to pack a lethal weapon for future bosses. However I sold everything except for my tranquilizer rifle and my P.E.P.S. somewhere along the way, including the almighty rocket launcher I stole from the D.R.B. Now I'm stuck with the aforementioned weapons, a single gas grenade, a single EMP, and plenty of energy restoratives. What do I do here?
No I think you'll be okay. I'm pretty sure there's weapons around the room (including a heavy rifle in the room right before the boss fight if its possible to backtrack) that should be enough to take her down. She isn't immune to stun attacks so use the P.E.P.S. or destroy the power generators around the room to stun her, then attack her.
I actually did backtrack and got the heavy rifle and I managed to destroy all the generators. Now I'm sitting at one EMP grenade and one gas grenade. The P.E.P.S. is virtually useless since by the time I switch to the heavy rifle and charge it up she's already running away.
Ah okay. Have you been able to find any other weapons in the boss room? There are lockers around the place that have a couple I think. Maybe if you try to get a lethal weapon you can equip faster and restart the boss fight - you might be able to deal damage while she's stunned.
Revolver's are great actually. It's obviously more effective when upgraded (you can upgrade it to have explosive rounds) but it might do the trick as is. Try it out, and if you still have the heavy rifle, you might find an opportunity to use that too to finish her off.