Most important facts I've noticed about your setup:
CPU: AMD Athlon II X2 220 @ 2.8ghz (factory listed speed)
Memory: 4.0GB (speed unknown)
Video Card: ATI Radeon 3000 Graphics (integrated graphics)
Just looking at your CPU I can tell you're sitting at right about the bare minimum "CPU" requirements, not to mention all the other things you're missing.
Your Memory is fine, don't listen to people saying you need above 4GB to play the game. Your system would only benefit with more memory (for gaming) if you first had a stronger CPU.
Integrated graphics are a definite out for this game, you need a
dedicated Video Card before you even start to think about running it.
What you can do:- Your CPU is fine, just at the bare minimum.
- You need to get a dedicated Video Card with at least 1 GB of video memory (recommend something in the $150-$200 range for best results).
- If you have a 300-450 watt power supply, you'll need to upgrade it to at least a 500 watt one, just to be safe.
Even after all this, don't expect a huge improvement.
Your CPU will prevent you from seeing any "
large" improvements, but I think you could benchmark at least in the 2000-3500 range, which is enough to run the game smoothly at a resolution of 1280x720.
*Thoughts*
Looking up your PC model number, ASUS lists it as coming with a FAR more powerful CPU at bare
minimum and I can't find any website that lists it as coming with that AMD Athalon II x2 220 as stock.
Did you perhaps build the PC on ASUS's website or did you get it at a retailer?
If you got it from a retailer for $500-600 you should feel taken advantage of. That PC model lists it as coming with a AMD Phenom II 1065T @2.9ghz, a far superior CPU with 6 physical cores.
(I have a PC with a AMD Phenom II X6 1090T, which is just a step above that. It benchmarks the game at 8000...)