As far as I can tell, there are no permanent stat ups, but there are temporary stat buffs and equipment to increase stuff for just as long as you are using them. For intelligence, the ones I know about currently available to you are Easter Beast Omelets (hunt Easter Beasts in Bomb Pit and occasionally when travelling between towns, hope they drop an egg in addition to the meat, Cook it with an Unglow Pill from Doctor Choppy) and Black Rollies (bought for 30 Gunpowder each in Last Elysium). Together, these will get you 2 more Intelligence. There is one more source of Int available that I know of, but... it's inside the suitcase! I'm not sure the exact target number, I think it's 6 or 7?
For room A5 and B6 in the bunker, the target Dexterity is 8, but having it that high just... lets you avoid the damage. Unless I'm missing something, you can't actually go inside or there is nothing in there.