Song in episode 14 of Ghost in the shell SAC 2nd gig
Not sure, but is it, From the Roof Top ~ Somewhere in the Silence (Sniper’s Theme) ?

List of Albums for Ghost in the Shell: Stand Alone Complex (Wiki)

Useful links for previewing the ost's, 

link 1

link 2

I think YouTube also got most of the OST's from the series but, I am not sure if it is available to your location.