Having had some time to think about it a bit more, I'd actually recommend the Lesser Chasuble of Fell Power over the Warlock's Scepter.  You'll be targeting touch AC, will be tiny size and thus already getting an attack roll boost, and will be invisible a lot of the time when attacking, so that +1 bonus to the attack roll really doesn't matter.  That means it's a question of the Chasuble's all-day 1d6 damage boost vs the Scepter's potential for a big damage spike on one shot, and I'd personally prefer the constant boost if it was my character.<br/><br/>Something to allow for some extra mobility might be useful for the leftover gold.  Chronocharm of the Horizon Walker, those anklets that let you teleport 10 ft as a swift action, that sort of thing might be good to pick up.