Is scripting an option here? Because you could make a script that detects when you are pressing left or right, and if you are, it can continuously decrease the angle or increase the angle. Then to position the "targeter sprite" you get the location of the player sprite and add some offset like this:
TargetSprite.X = PlayerSprite.X + Cos(AngleRadians) * 100
TargetSprite.Y = PlayerSprite.Y - Sin(AngleRadians) * 100
As the player presses left or right, you would increment or decrement AngleRadians by small amounts like:
AngleRadians = AngleRadians + 3.14159265 / 18