What outfit. . .

cclesue

Or better yet what helmet is this. I can't find it anywhere.

And while we are at it what weapon is this? 

nemesis10

A retextured version of this: http://www.daz3d.com/mech-gear-for-genesis-2-male-and-female-bundle  I remember that helmet very well... Don't know the gun though

fatel666

The gun is http://www.daz3d.com/mks-tactical-sniper-rifle-and-poses :)