Here is a freebie - it depends on HOW realistic you mean.  If you want a "reasonable" one for A3, then go here and scroll down; you'll find two by shukky.
http://posernightmare.com/download/index.html

By "reasonable" I mean they are believable - not Super Hero CosPlay

(While you're at it, get the free 100 poses for A3 below it - I use these all the time & find them useful for general life; not so bizzare artsy poses as most packs how now.)