http://us.battle.net/wow/en/characte...hadowee/simple
I am assuming this is you.. First I would begin by fixing your shoulder enchant to the epic one, and the gems from 40 agi to 40 int..
Second if you really want to hit 2589 haste that badly, you could sacrifice a minor amount of hit rating in order to make it there, put a +20int/haste in an orange slot, get +65 haste to bracers, reforge your 2nd ring to have haste.
There really shouldn't be a huge dps loss by not hitting it, I'd recommend getting a warlock.. and making it far easier. Otherwise, upgrade a few other items and you will hit it naturally. Keep the 403 staff and nuke things
Edit: Not always perfect, but askmrrobot is a tremendous tool for getting a good baseline of what you should gem and enchant for your ideal dps output.