Do the Animation Again

Hey,

i have a problem with an animation. Its the first time i try to create a game.
There is a cube, which should be moved with the arrows. If i click right arrow it should start one animation to go one block to the right side.
This animation works fine, but only one time. If i click it a second time it doesnt work.
So i used the left arrow to stop the animation, then it goes back to the start.

I attached the project. I hope you can help me.
I just want to know how to repeat this animation, that the cube can go more blocks to the right side instead of one block.
The other animation can i produce myself

Thanks in advanced

Project: http://cursedm3dia.bplaced.net/Files/CubeProjekt.rar