Where can I find the extended AO settings just like in the viewport one?
Most of those have similar properties in the gather panel in your screenshot for the Blender Internal ambient occlusion:
- Samples - in gather panel
- Distance (attenuation distance in BI) - in gather panel
- Strength - Factor in AO panel
- Attenuation - Falloff Strength ("Falloff" must be enabled)
Note: You will probably want to change the AO to multiply instead of add to further mimic these settings. It is also important to mention that these are two different AO systems and don't have the same functionality.