You should able to set up the game with nice settings. If I were you I would do the following:
1. Play at each level on video settings. Note the fps (Type: ` perfoverlay.drawfps 1 (then hit enter) your fps should show up.
2. As you try each settings limit AA to 2x. You dont get much for the loss in FPS after 2x.
3. As you try each setting play with the field of view and note your FPS.
4. Test your Ping ( http://www.pingtest.net) and dont join servers higher than 80.
As for your rig, make sure you do a clean driver instal of the latest driver. Also try to repair option for B4 game just in case.
Last: Try to OC the gpu/cpu. I'd only do this if your need the extra 5 fps to get a steady 60 fps at the higher settings.
Using these steps I was able to play the game with a gts 250, 7870xt, and now a 7970. I still can't max all things out and stay about 60 fps tho. I run ultra/high and 2x AA but have my view maxed out. The trick to having a good time is high fps and settings that help you spot ppl.
Good luck.