I am going to guess your stats probably looking something like Str 14, Dex 18, Con 12, Wis 18 with monk 9/ftr 1. Given the gear you have listed that would put you at AC 20.
Assuming your going to take monk again next level that will bring it upto 21. Now, lets look at what can help that.
Choices
1) Periapt of wisdom +4, Gloves of dexterity +2 Cost: 20k -- Raises AC to 23/24, reflex save by 1, will by 2.
2) Amulet of mighty fists +1, Gloves of dexterity +4 Cost: 22k -- Raises AC to 22/23 damage by 1
3) Amulet of natural armor +3 Cost: 18k -- Raises AC to 23/24
4) Sell ring of protection and brooch-- Buy Ring of protection +3 and Periapt of wisdom +2 Final Cost: 18.5k -- Raises AC to 23/24, will save by 1
5) Sell ring of protection and brooch, and cloak -- Buy Ring of protection +2, Periapt of Wisdom +2, Gloves of dexterity +2, Cloak of resistance +2 Final cost: 19k --- Raises AC to 23/24 Will save by +2, Fort +1, Reflex +2
I would actually suggest number 5 as your gamemaster will probably not worry too much about the item increase as it doesn't appear that any of the items are overpowered in and of themselves. They appear to be nothing more then increases in items he has already given. Also, in the end it will probably help you for passing items onto other players later if need be. But like I said that is just my opinion.