Just to put things in perspective, 19 extra skill points in Ice Arrow adds 1.9 seconds of cold duration to Freezing Arrow. Just two cold damage charms will add 2 seconds of cold duration. It's much more efficient to just place 1 point into Ice Arrow as a prerequisite and leave it at that.
Eye of Etlich has a randomly generated 2-10 second cold duration. So there's a chance that it wont be as good as hoped for. It doesn't show it on the item though, the only way to test it is to unequip everything but the Amulet and hit something in Normal difficulty and see how long they are chilled for.
Even better though is Raven Frost unique ring. It adds 4 seconds cold duration, you'd do best to be using two of them since they absolutely rock on this build. The mana, the Dex and AR and Cold damage are all useful mods.
All charms will each add 1 second of duration, regardless of size. This goes for all cold damage mods on charms. So naturally, Small Charms would be best.
You should generally aim for around 20 seconds total added freeze duration with your items. It's reduced to 1/4th in Hell, so that's still 5 seconds of freezing time you'll have with each Freezing Arrow.
I suggest you put those extra points you would have put in Ice Arrow into Strafe instead. That way with a decent bow you should have two types of damage (Cold and Physical) at your disposal.
For the gear, it's usual Bowazon gear, but you should focus on getting +Bow skills on your gear, as well as having a fast enough attack. Just make sure you have some Mana Steal with your items as well, so you can keep shooting Freezing Arrows.