moving weapon on touch (or mouse)

I know how to get a target line from my weapon to wherever the player is aiming.
Basically, the game is a sidescroller so the only possible movement is on the X & Y. Z being at 0.0f. So I need to be able to move the weapon on an angle up and down as per the user touch.

It’s a mobile game but if there’s an example with a mouse, I will be able to go from there.

My question is, how do I get the weapon to follow or at least point in the direction that the player wants?

And my second question would be, how do I handle the player animation of the weapon moving?

Any links to tutorials or other would be appreciated.

thanks,

UPDATE :: just so I can be clear here, what I need to know is how do I move the weapon in a players hands (So the arms of the player are moving as well) to follow the touch (on mobile) or mouse on the X & Y axis.

These links are for animation part that you were interested in:

Animation intro: (Rabbit)
http://video.unity3d.com/video/3005614/animation-view-intro

Animation example: (Weapon)
http://video.unity3d.com/video/3005963/animation-view-imported