What do you mean with controlling the crosshair with the right stick. Like in omnidirectional, when you move the stick, the cross hair moves around ?
Or a simple cross hair in the direction of where the player is aiming ?
The first one is rather hard, as the rest of the game is not suited for that movement, unless you overhaul a lot.
The last one should be easy:
add an image point to the player sprite, to the right of the player (how far you would like the crosshair to appear.
With the crosshair somewhere in the layout, and pin behaviour added.
Crosshair set position to PlayerGraphics.imagepointX(2), PlayerGraphics.imagepointY(2
Crosshair pin to PlayerGraphics.
or
Crosshair set position to object PlayerGraphics at image point 2
Crosshair pin to PlayerGraphics to imagepoint 2