There is a program called S.A.M. or Steam Achievement Manager. With it you can unlock absolutely any Steam achievement. Of course it does come with a warning that there is always risk in doing things like this like potential bans. It is not recommended using this on VAC protected games like Counter Strike, Half Life 2 or Left 4 Dead.
I made a video on our YouTube channel to demonstrate it working, so check it out!
The video also demonstrates another program called Idle Master which gets Steam cards where the requirement is just to play the game for a set amount of time.