Apparently comment link on that part of the quest chain doesn't work. I've reported it to thottbot staff, meanwhile would like to leave one here.
Anyways, what you need to do with the quest is use the scroll you obtained behind Anastasia. Use it in the Apothecary area. It spawns some sort of Arcane Elemental which you need to bring down to 1 health thus "stunning" it. While it is stunned, use the Container you obtained behind the quest giver. Elemental vanishes and leaves Filled Container Coffer on its place. Pick up 3 of those to finish the quest.
The reason I posted this comment is because my quest turned out to be broken. I kept getting 3-4 lvl 16 elementals that were charging me all at once right as they were spawning. I've died twice until I figured out something is not right :) If you happen to get same thing I did, kite 1 of the elementals (damage it periodically - fire blast, arcane explosion, wand, w/e) until the others leave you alone (they're not linked). You have to bring your victim back to the Apothecarium area though, otherwise Container will not work on it. Good luck with your quest.