Help with build, set bonus vs stats/ilvl

[Nova_xp]

Spec: Frost
Armory: https://worldofwarcraft.com/en-us/chara ... dan/novene" target="_blank

I'm a bit newer to the game, and I'm having trouble figuring out what build I should be using. I have some gear that is good ilvl and has good stats for my spec. Then I have several pieces of my tier set that are a bit lower and sometimes have stats that aren't as good for my spec.

Set

Head: https://puu.sh/wdMxK/a52cc4b3ca.png" target="_blank
Shoulder: https://puu.sh/wdMAi/f0af5ea6e7.png" target="_blank
Chest: https://puu.sh/wdMAT/db1d738dfc.png" target="_blank
Legs: https://puu.sh/wdMFa/f847b7cac9.png" target="_blank
Hands: https://puu.sh/wdMFP/4fc93841b8.png" target="_blank

Other:

Shoulder: https://puu.sh/wdMMz/08a268beba.png" target="_blank
Chest: https://puu.sh/wdMNm/27ad88c804.png" target="_blank
Legs: https://puu.sh/wdMNY/be3b3caa10.png" target="_blank
Hands: https://puu.sh/wdMOv/097b2ea752.png" target="_blank

The set head is the best one I have, so I'm using it. I've also been using the set hands. I'm really looking for input as to what I should be using along with that. My stat weights from my sims put crit, haste and int on the same level, while mastery is about half the importance. I'm looking for some opinions on what combination of gear I should be using, since I'm not sure how important the 4 set bonus is vs better overall stats.