How about a baseball? It would be kinda like the sticky grenade, where you can charge it up to get a throw for more damage, or you can just chuck it at people quickly. If they add that they should have the victim have blurred or reduced vision for a split second.
Or maybe like someone said, a blast shield, but from the old CS games where you can shoot the pistol too. Have him get reduced speed while doing that, that would be interesting.
And finally... a more powerful pistol instead of the dinky little peashooter.