Since you dont have the 264 badge chest yet, don't buy it. Your T10 chest will be better because as you gear out you will be able to get into ICC 25 pugs and obtain tokens to upgrade it to ilvl 264. The 2p and 4p Bonuses are absolutely amazing, and I would not recommend passing them up. As for the remaining ArP, you should be eating ArP food.
Also I recommend you use the Relentless Earthsiege meta gem. +21agility, +3% increased critical damage. Change the dreadstone in your chest to a nightmare tear, and the dreadstone in your boots to a +20ArP. This will leave you more room to work with your gemming as you obtain upgrades.