Thanks for suggestions everybody.
Slowly but surely getting there.
There is a bug in the page http://us.battle.net/d3/en/profile/Whisper-6439/hero/1390664
it shows me with only 43% CHC. I have 7% owed to me from the Natalyas set bonus, which is not showing, so I am in fact at 50%+5% = 55% CHC.
I can pinch another 30 AR on Tal's Pursuits without blowing the budget. Pushing higher AR on those might cost me a bit. though.
Witching Hour with high AR is expensive, but I should be able to get at least another 20-30 without crying to the bank, which ought to push me well through the 600AR mark.
You get AR at a ratio of 10 INT = 1 AR, correct? If so, grinding Paragon Levels will net me another 15-18 AR just from the extra Int. I guess picking somethings up with big Int numbers may help a little there.
Been toying with the idea of swapping out my Innas & Amulet for a Blackthornes Amulet and Pants and stick a Mempo on to make up the IAS.
My Mesmerism Maw Amulet should fetch a little bit of gold, I wouldn't mind a price check on what people think it would be worth?