Trouble with animations.

So after doing some research on this I was told that I needed to have my animations layered, so that more than one could be used at a time. The point in my game is an 3D Action RPG which requires constant movement and other animations, my problem is this.

My Character Controller script and Camera script are both custom, and in those scripts I have it set so that if the player is moving, than it will play the walking animation, and if it's not it will play the idle animation, I did this through means of the CrossFade function, so what ends up happening is.

In my combat script I have it set up to use the attack animation on mouse-press, so when the mouse button is pressed down it should play out the attack animation, using animation.Play(String), although it does not matter which method I use i have to mass-click the mouse to get the animation to play through and it's choppy, I'd like one fluid motion, I can understand animations conflicting, such as walking and attacking at the same time, which is fine and understandable, Although, how would I go about stopping the Idle animation, or over-riding it so this one has priority? Thank you.