I’ll agree with Balasarius in that monks can be quite good at getting high AC, but you really have to know and therefore use the system. First off, a minor spoiler about magical items: there are monks robes. Three, to be precise. Each are gated to a specific alignment (LG, LN, and LE). The LG gives you +5 to your AC and +1 to attack/damage on your unarmed strikes. LN is +3/+3, LE is +1/+5.
That said, you also have styles, one of which is available is Crane. Heading down this tree (and taking supporting feats) and then fighting defensively when your monk is the primary target of a nasty brute will boost your AC considerably. Turn that off and do Dragon or Pummeling when your monk isn’t getting focused on.
Non-spoiler magic item stuff; while anything boosting your Dex will help with AC (and initiative), don’t forget items (and spells) which boost Wisdom (standard monks) or Charisma (Scaled Fist) boosts will also boost it. You’ll be able to find items with hefty bonuses as you continue on. Oh, and the standards like Mage Armor, natural AC, etc…
In terms of gameplay, until you get there and while you still have a semi-squishy monk, I’d bring in a tank to aggro the biggest bad guy first and then your monk to support via flanking.