Obrysii, Umbriel can give you Greater Mage Armor instead of you using your wand - it's an extra +2 AC, it's more resilient against dispels, and it's an infinitely renewable resource
I can also give you Extended Spiderskin, which is +5 natural armor.
I don't know of a wizard spell that gives a long-lasting deflection bonus to AC. There are cleric buffs that would help further, like Recitation and Mass Shield of Faith. Even with just Spiderskin+Greater Mage Armor, though, it looks like that would take your all-day AC to 37, which seems pretty good.
The classic dragon offensive buff is Fires of Purity, which is both in-flavor for a gold dragon and gets more awesome the more attacks you have (it would also go very well on Rhion). Umbriel doesn't have it at the moment, but if she can find a wizard willing to trade spells, it would be on her shopping list (or I could buy and scribe a scroll, but I might ask you guys to chip in, in that case, as buying new high-level spells as scrolls gets expensive fast).
Xiuhcoatl might also want an extended Resist Energy (Cold), and I'd be happy to give you an extended Heroics for Power Attack or another feat of your choice. I suggest Power Attack just because Godot's awesome buffs make hitting rather easier than usual
Dragons are fun
to buff (as are warshapers, for that matter)
Also, for wondrous items, if we have downtime and get some XP rewards, I am
willing to craft stuff for the rest of the party, you don't need to buy everything from ripoff merchants