How to poison Simoc with a low Intellect and Resolve build in Pillars of Eternity?

I have a rogue build with rather low Intellect and Resolve, base values are 12 and 9.

When trying to poison Simoc, there is a huge stat check for both Intellect and Resolve. I need to get both those stats to 19/20.

How can I boost my rogue to those stats?

I already have an amulet for +2 Intellect (Unwavering Resolve) and a ring for +2 Resolve (Serel's Ring). I guess I have to find +3 items, but where?

Also, is there an inn room that will boost those too stats as well?

And are there consumables than I can eat before talking to Simoc that also add a boost?

I assume that I will have to boost my stats for up to +7 points for intellect and almost +11 points for resolve. Is this even possible to achieve this kind of boost in the game and if so: how?