If you're able to and comfortable with overclocking your 530 I would, many benchmarks show that for w/e reason once you start increasing clock speed past 3-3.2GHz FPS starts to rise quite dramatically.
Other than that the game really likes quad cores over dual cores, your graphics card isn't too hot either but the game is notoriously CPU heavy so I would make your first port of call overclocking / investing in a Quad to overclock before worrying about the graphics card.
On the game I would consider running at Medium and not high, there is very little visual difference between them but I will try and break it down:
Level of Detail:
This mainly controls how far away from you foliage/vehicles/players/various models are rendered at full detail. You will see in your settings.ini these can be individually set.
- Low is quite bad, you have to be stood practically ontop of something to have it rendered fully.
- Medium has things full detail quite far away, far enough that you probably wouldn't notice them 'popping' without specifically focusing on an object at distance whilst moving towards it.
- High has them rendering very far away, at a noticeable performance hit. Wouldn't class it as necessary even if you had an amazing PC.
Textures:
Doesn't seem to so much effect the resolution of the texture maps (might be wrong) as much as whether it includes various blended overlays. A wall might have a rather muddy looking base texture which isn't that great, but then detailed brickwork or various other decals are blended over that. Usually texturing is memory dependent anyway and impacts little on performance as long as you have the capacity.
- Low has no overlays, you get the base blurred texturing and everything looks pretty bad.
- Medium has the overlays everything giving everything a much more realistic and defined look.
- High... the developers insist that certain textures are higher resolution with this but I would really like an example given, I'm yet to see a single textured surface in the game that looks better on high than it does on medium.
Effects:
Not entirely sure how much particle effects are controlled by this, not noticed a difference between them low through high, though it does seem to control the bloom setting and low disables it, changing between medium and high will have you want to go back to your settings.ini to disable.
Shadows:
Shadows appear at more crisp, although I'm pretty sure the distance at which they maintain this detail isn't effected by setting it higher, just the shadows immediately around you.
- Low has very ugly shadows
- Medium has decent but still noticeably blocky and undefined edged
- High looks good (little jaggy still but not much you can do about it) pretty much the only 'high' setting in the game that gives a good visual upgrade
You then have your other settings, HBAO can knock the FPS a touch so that can be disabled for increased performance (makes shadow looks more defined, specifically in geometry rich areas) AA / AF are a no brainer.
Sound options do play a role in performance, in the settings.ini changing the quality to low can increase performance somewhat, I haven't tried the next one myself but have seen people saying that within the Windows control panel for your sound, lowering your frequency/bitrate can have sizable increases (IE lowering 48Khz/24bit to 44Khz/16bit).