Well you could have 1 sprite for each level that has 3 frames, frame 1 - 1star, frame 2 -2stars, frame 3 -3stars.
Lets say 100pts gets you 1 star, then you make a global for each level that checks the high score for that particular level.
Condition would be a sytem condition, check two variables, action would set the frame of the sprite
high score >= 100 & <200,
play animation 1
high score >= 200 & <300,
play animation 2
high score >= 300
play animation 3