I can't look at the capx right now, but the basic premis is to simply do this.
Add a variable that becomes active every time the player presses the attack button
on keyboard pressed "A"
->set "attacking" to 1
->play animation "attack"
then in the section that has all of your movement stuff.
add a condition that only allows the player to move if "attacking" is set to 0
on keyboard pressed "right arrow"
(system) attacking = 0
-> move player right.
this way it will only work while not attacking.