Should i replace or buy new?

[Gameboy93]

Hello i have a ;
Motherboard: H-I41-uATX (Eton)
Display adapters: Intel G41 Express Chipset
Processors: 2 Intel Celeron CPU E3300 @2.50GHz
Computer: ACPI x64-based PC
Power supply: 250W
RAM: 3 GB

Subscores:
Processor: 6
Ram: 5.9
Graphics: 3.9
Gaming Graphics: 3.4
Primary hard disk: 5.9

What video card i can use to run Diablo 3 and DotA 2 on highest graphics possible for my rig?
Or should i get a New computer?
What setup would run skyrim on Ultra graphics?

 

[Gameboy93]

Well my budget is either a new video card for my current rig (have $120 dollars) or if i have the time i can travel to a bank quite a bit aways for $1300 dollars