I'd suggest you give Piehole SNS guide a read:http://us.battle.net/d3/en/forum/topic/8728753771
In general for CMs, it's not about the sheet DPS as much. You need to balance out good freeze, good mit and DPS. Freeze and mit give you the ability to change out the defensive skills for offensive. Because CMs deal damage with many skills at once, we refer to a "damage multiplier" - that is, the approximate DPS we put out over our sheet DPS.
Here are good parts at what you have right now:
-You have min suggested APoC (min 18)
-800 LOH is good. Not great, not terrible.
-Your current build is acceptable
Now here are the bad:
-You're just under 2.51 breakpoint. You want to be slightly over, not slightly under. For a new CM wizard, you should aim for 2.73 APS - it's the breakpoint that's easiest to reach and gives you great balance in DPS and survivability. There are some terrific 2.51 wizards running around, but their gear is worth significantly more than normal (~10b+)
-You have very low mitigation (http://d3up.com/b/1058149 - look @ total dmg reduction). As a minimum, CMs try to run with 87% or higher. Most good CMs have 89%+. Since most CMs rely on LoH to stay alive, we regain life at a steadier pace than other classes. High level of mitigation lets us tank through the worst hits and survive while LoH heals us to full.
Those 2 bad points you cover with your Skill choices. To deal with low IAS and being under the breakpoint, you're running 2 active and 1 passive skills (cold snap, bubble stretch and evoc). This tremendously helps your freeze.
To deal with lot mit, you again run 2 active and 1 passive defensive skills (prismatic, crystal shell and galvanizing ward).
If you can get your IAS to 2.73 (with no buffs) and grab ~200 more AR and ~500 more armor), you can switch out your defensive skills for offensive skills and run a real SNS wizard. Your multiplier will be much higher and you'll be able to provide much better support for your team, either via re positioning (tele), time warp bubble, running conflag.. etc. I mean, running Cold Blooded instead of galvanizing ward and Time Warm instead of time stretch basically adds 40% more DPS by themselves.
If you want to have a GOOD 225k wizard, give Piehole's guide a read.