replace those hit gems with damage ones (even green wotlk ones are cheap and are great - 14dmg for 3g, kk). that should get your damage a lot higher.
I've always been a big fan of frost for leveling, just makes everything so much easier.
A few talents that you have that are not very helpful:
imp scorch (how often are you using it for the crit bonus?)
living bomb (most/all mobs should be dead in far less than 12 seconds).
Get some points in impact and dragon's breath and blastwave for leveling.
It's like you are trying to put together a raiding spec for leveling (does not work well unless you are very well geared, which you aren't really).