Here are my specs:
Pentium® Dual Core CPU
E5300 @ 2.60GHz
2.62GHz, 2.00 GB of Ram
ATI Radeon HD 4670

The best performance in battle I got was 30-40 FPS. I would like that 60 fps in battle if possible.

Could you tell me the best config., graphics, speed hacks and advanced(possibly any others that would increase the performance speed) for my PC?

Update, I've been able to run it at a stable 55-60 fps with GSdx (SSEE3) 0.1.15.
But the action is all shaky, how can I fix that?

Try different interlacing settings.

Just go:

Config -> Graphics -> Interlacing

You can switch ingame with F5.

BTW: Nice Computer xD Reminds me in mine lol