Hi Raven,
First create a back-plate for the scrollable area. This should be either black or transparent and placed in the area you want the scrolling text to appear, place it in the area you want and make it a child of the object you already have.
Then create a text object for your scrolling media information. Place it over the back-plate you just created, make the background transparent and make it a child of the back-plate object.
Now when you have a new media item to display set the text of that text object to that description.
Now to make it scroll you need to create a scripted timer to move the text, one pixel at a time to the new position of the text but because its a child of the back-plate object it will be clipped by the region of the back-plate.
If you want the text to cycle repetitively you may need to create two text objects that fit end-to-end so that the start of one can be seen at the same time as the end of the other. This can be achieved by cloning the original object when its required.
Regards
Wolfie