As the title says, I'm looking for some advice on what to upgrade. I'm currently 5 (sometimes 6) boxing WoW. All boxes are visible across two monitors.

My current system:
  • CPU: i5-3570K (not clocked)
  • MB: Gigabyte Z77MX
  • Ram: G.Skill 8GB DDR3 (2x4 sticks)
  • Video: GeForce GTX 460 (not clocked)
  • Storage: 70gb SSD - 1 TB HD
(If I left anything out just let me know )

I'm not sure why I haven't over clocked either my CPU or GPU, just irrational fear of screwing stuff up I guess.
I have a budget around $250 (before tax) but I could do a bit more if you guys think it'd be that big of an upgrade.
As of now I'm just thinking of a GTX 760, as I would really like to upgrade to 3+ monitors since as far as I know the 460 can't go above 2.
Thoughts? Any advice is greatly appreciated!