Go for the weapon, it will last you until your guild kills Vashj (if you get lucky on drops) or Illidan.
With the weapon, you get +89 healing, +10 int and +14 stam over what you have now.
The chest(with a Teardrop Living Ruby) gives you +57 healing, +8 int, -15stam +6mp5 and -27 spell crit compared to what you are currently wearing (and ignoring the +10 stam leatherworking patch you've got on it since I assume you would use +6 all stats on the badge one if you got it).
Either way you will end up buying both most likely, but for myself, I'll be buying the weapon first (and I'm using the same chest piece you are).
Edited, Apr 11th 2008 6:27pm by Khalane