I'd like to first of all thank everyone for taking the time to read this and giving me advice. I built this computer a long time ago and would like the best plan to upgrade. I was thinking of doing it slowly about 200 a month and buy the parts bit by bit. I saw the marathon build and was looking at the 1000 build. I only really need to replace the core components since I have operating system, power supply, and case. All I am looking for is to run world of warcraft and star craft 2 at optimal speeds.
My current rig.
Mainboard : XFX XFX nForce 790i Ultra 3-Way SLI
Chipset : nVidia nForce 790i Ultra SLi SPP
Processor : Intel Core 2 Duo E8400 @ 3000 MHz
Physical Memory : 4096 MB (4 x 1024 DDR3-SDRAM )
Video Card : ATI Radeon HD 5800 Series
Hard Disk : Western Digital WD30 00GLFS-01F8U SCSI Disk Device (300GB)
Hard Disk : Seagate FreeAgent Go (250GB)
DVD-Rom Drive : HL-DT-ST DVDRAM GSA-H62L
Monitor Type : Samsung SyncMaster - 23 inches
Monitor Type : L86080584211 Acer AL1916W - 19 inches
To be perfectly honest, I don't see any reason why your current system could not run those games smoothly at high settings and I'd probably look to other issues before spending a ton of money on what may be an unnecessary upgrade.
As for your projected upgrade, unless you're planning on a heavy multi-use system that will actually utilize all those processor cores, I'd stick with Intel Quad-Core processors.
First I'd say save up and buy it all at once. Technology changes too fast to finished a build 4 months after starting. Unless you start with something that will improve you current build now, like a graphics card or PSU (which you neglected to include), you are better of doing it all at once.
Next, if this is a gaming build you may want to switch to an i5, unlocked if you're an overclocker, or what you're budget allows, which the corresponding changes.
Lastly, while it won't make much difference for the two games you specified, currently the AMD 7xxx series with the 12.11 drivers a CAP2 profiles has the price/performance edge on modern games, especially with overclocking. Again, won't matter if you're only playing WoW and SC2, and may change at any time, but FYI.