HPM-Board

So I recieved a new (older) PC which Is from I think 2008 and nobody in my house needed it so I thought why not take it.

Here are the Specs:

Intel Core 2 Duo E6750 @ 2.66Ghz
Microstar MS-7502 Motherboard
2x2 GB DDR2 Crossair Ram @ 800Mhz Dualchannel (I upgraded from 2GB DDR2 @ 667Mhz)
8600 GS Graphics Card 256mb (I need suggestions for this one, because it is the worst part of my config by far -.-)
CD/HD-DVD/Blue-Ray Burner
8 USB Ports, Sound Card on Motherboard etc.
2 HDDs, One internal 500GB and an external 650GB which is connected via e-sata so it is pretty fast for an external
350W Power Supply


Questions:

1. Should I overclock my CPU to say 3.0 oder even further? Or not at all? (Not even sure If I can overclock it with this MoBo.
2. Is the Saphire Radeon HD 6670 a good choice? I want to stick around 80-120$ or say 100EUR while having a good graphics card which works with my 350W-Supply and still delivers a good amount of power.
3. Do you have other improvements?

hello, i wasnt able to find specifications for motherboard but if your motherboard has two PCI express slots it would be quite wise choice having two cheaper graphic cards that have support for Crossfire technology (two cards are 190% effitient but can be much cheaper).
Also i wouldnt suggest overclocking your pc because it might be enough, its up to you but 350W power seems very limiting and i dont know how is your cooling system.
Last thing, the only drawback i could see in that is DDR2 ram. if you can, get DDR3

DDR3 is not supported sadly because the motherboard is (insert bad word).
The DDR2 Ram is pretty good though it was 45EUR and it's Crossair.
Cooling well... My CPU as far as I know is around 45° when maxed out.
And two graphic cards would probably blow my power supply up (lol)