That link posted above should help you squeeze out some frames, but from your specs you are on a laptop which are not the best gaming platforms - especially when it comes to games that are both CPU as well as GPU demanding (a-la Arma III). Although you should be able to get some decent frames in ARMA (after following the steps in the link), I would expect your settings to sit in the low to medium range for visuals if you want to keep the frame rates up.
It really comes down to: do you want to see pretty trees and far away mountains, but shoot at slide shows on the field - or - see some pixely trees and blurry mountains from afar, but have smooth targets on the field that you can easily track with your scope?
