Alright, let's see here, methods for getting AR. Well, one angelic ring and the ammy adds around 6.5k ar to my 99er, while two rings and the ammy adds right around 13k, so that is always the best option. Other items like metalgrid and raven also add a good deal as well, if you find yourself severely lacking.
Charms would be your next best choice, as you can get fine/vitas with 20 each on them, so a stacked out inventory of 39 (leaving room for annihi) fine charms can add an extra 780 base to be multiplied by your skills; you can always use grands as wel, as they can break 100 each. And of course annihilus can add up to 80 base on a perfect roll.
The enchant charges on Demon Limb are likewise very nice; the amount it helps varies, but in my cast, casting the enchant and switching back to my original weapon added around 4k ar.
Finally, that point in battle cry goes a long way, halving enemy defense. It doesn't have as much of an effect in pvp, but it'll still gain you a few %. I typically don't suggest melee dueling in the IK suit though, as without a shield, you're not going to be very effective.
-Hal