Power Bar Help

ATNK1

I am trying to create a power bar for a sporting game for the ipod, some what similar to the bar in football games for free kicks etc. Basically i have created 3 blocks a large red, smaller orange, and smallest green. I have also created another actor (a block) to move from the top of the bar to the bottom of the bar and the user could stop the bar at a certain area. The green being the best, providing an accurate ball shot. The orange being less accurate and the red being the least accurate.

Firstly my problem is getting the block to move up and down almost in a loop, i have got it to move from the top to the bottom using timers but i cannot get it to continue on a loop.

Then i would like the user to be able to stop the block at a point the user wants.

I am sorry it's a little long winded, i am fairly new to this and it is a little complicated.

Thanks in advance, ATNK1