I personally would save up the money for wrath. While you are saving up money, go ahead and run lvl 70 heroics, join pug raids for lvl 70 stuff, all the 80s just want the achievement, so you will likely get all the loot. Then once you get wrath, you have a head start in gear.

You could also take this opportunity to lvl up many alts to 70. Max out what you can/want to and you will have less work once you get wrath.