A bit more crit chance would help, as would more dex & avg dmg.
Amulet you should be able to get a decent dps boost as yours has no avg dmg, middling cd and low dex. I paid 16m for mine which has 100-ish dex, 50 avg dmg, 9% cc, 70% cd (it would be a 15.5k dps boost for you) though your amulet is a problem since it contains so much of your vit. You want to spread that vit around on different pieces so that you don't take such a hit when you upgrade that slot.
Nice ehp rolls on the bracers but pretty low dex. I'd be tempted to keep rolling those hoping for similar ehp rolls but 270+ dex.
Witching Hour would likely be a good upgrade in the belt slot, though it could be pricey having to get AR rather than a single resist.
Pants I'd switch to vit rather than resist to make the amulet switch easier.
The biggie for me though is Nat's. They're not great for ehp, especially when compared to Ice Climbers & a decent rare ring. I'd be tempted to look for two rare rings with 40+ dmg, 70+ dex, 4.5+ cc and either IAS or CD (CD is cheaper) along with some resist and/or vit. Pair those up with a pair of 220+ dex Ice Climbers with vit and whatever random rolls you fancy - either move speed, armour or single resist. You'll likely lose a little bit of dps, depending of the rolls you can find (if you're lucky you might even gain dps!) but you'll gain a ton of ehp which would make switching out that amulet so much easier.
I'd replace that hellfire too - get a rare with the same stats recommended above. Only reason I run hellfire is that mine out-dps's my old dps ring.
Here's my monk now if you want to look for ideas (EHP is a little low right now as I made some recent upgrades...hoping to get a new ring to replace the hellfire to help with that):
http://d3up.com/b/618190/shyla-backlash-lightning
Oh, and @ xero: Yes, time bubbles do stack
And another edit: Regarding OWE: Meh, I don't really double stack resists anyway, other than boots & shoulders so if I can get a single resist that's higher than the AR resist in that slot it'll open up the other rolls for other stats like move speed or pickup radius.