[Oscuro_Sol]

To start your stronghold for House Telvanni you need to get a construction contract from Dren (done) and 2 Daedra souls.
My first question is if you can buy a soul gem that is already filled so you don't have to run into some ruins (I'm a low level >_<). I already stole the Balmora mage girl's winged twilight soul a long time ago, so I just need one more soul. I know you can summon Daedra and then trap their souls, but I can't take on any of the "high challenge " Daedra yet, I'm just not good enough at this point. Anyone know of any stores you can buy a filled Daedra soul at?
Second question (mostly out of curiousity) is why on earth do you need soul gems to build a stronghold? Did I miss something in the dialogue or...?
Thanks in advance,
-Osc