I agree that you must re-gem; however, remember you will need 2 blue gems to activate your meta gem.
And I must disagree with the Dk that suggested you use death coil. As a frosty you have no reason to ever use death coil unless you are not able to stay within melee with your target, frost strike is the runic power dump you will be using. Festering strike is also not needed. With the howling blast glyph you will be reapplying frost fever constantly along with using plague strick to activate death runes, keeping your deases up should be no problem. Now to reforging, hit rating to cap, expertise to cap, no exceptions. After that reforge haste and crit into mastery. Finally, for the sake of Dk's everywhere, get a new helm.