Optimizing Contact Other Plane

[HMS Invincible]

I'm in a hurry right now with the spell, otherwise I would just cast it and deal with the loss of int. I want both a truthful answer and want to avoid the loss of int for longer than a week. Is there any way to boost my int check? I've got 15k left to spend on magic items. I'm deciding on the dc 14 deity, and the amulet of second chances to re-roll if I fail the check.

Is there an item like the circlet of persuasion, but for intelligence checks?

[Hirax]

The Spell Compendium has the spell mechanus mind, which would help.

[HMS Invincible]

Oooh, good stuff.
Let's see, I have:
+4 enhancement bonus to int
18 starting int
+2 from levels 4 and 8
That gives me a +7 to int checks.
Mechanus mind makes it +9, that ought to help.
Combine that with amulet of second chances, and I should be fine.
If I use all my questions to reconfirm the first answer, I should be able to get a true answer with minimal error or failure.

[Sudain]

If I were a DM I'd have the deity give you the same answer as you got before, true or false. if I were feeling generious I'd allow a question that asked if the frist question was true or false and give a true/false answer for that.

[Tyndmyr]

Simple solution...if you have to roll back time, contact a different diety than the first one.