Upgrade Path for Video

Hi Team
I have to take sometime off WOW for about 4 months, I am going to get back into the game next month. I am thinking about upgrading my Video card.
My current config
q6600 not overclock
8 Meg of RAM
4870 1 GB Video card
500 wd 7200rpm HD
30 SDD drive (syslink Wow folder)
Windows 7 64
4 19" (1650*1050)
I was using a 2nd machine to run my main and 4 slave on this one. It was running fine but I want to run all 5 toons on 1 machine.

I will like to run 3 monitor in a H config, 2 monitor turn on edgewise side on each side of middle monitor. I have tried to add a 2nd video card (4670 and 8600gt both 1 gb, change the Pcie to 8*8) but the result was disapointing,

I am thinking about getting the new 5850 card and try out the Eyefinity and see if this will be better. Do anyone have any thought on this. Is is better to use the DP port for the middle monitor, and the DVI ports for the side monitor, will it make any different?

Main 1650*1050 on the middle monitor on high detail
slave 825*525 *2 on each of the side monitor on min detail

I might try the 2 video card again, is there a trick to get this to work without killing my framerate?

Thks for any help on this.

if you want to attach 3 monitors to the 5850/70 you definitely need one with displayport, since you can only use 2 over dvi or hdmi :)

even though i haven't seen eyefinity in action i doubt it will make any difference which monitor is at which port ;)