Texture clamping at center? (unsure if that's how it's called)

The selector image I use to show user the selection he’s made after a click on the screen looks like this:

It might be hard to see exactly, but the selector is “attached” to the star on the bottom left as is expected (since texture coordinates start there), but I want that image to be attached at the center so the selected star is in the middle of the selector. I’ve tried to find a way to do it, but couldn’t.

Help would be appreciated.

PS: Almost forgot. Is there a way to have texture scaling disabled? By that I mean that if I click a star far from the camera, the texture above will be scaled and sometimes is pretty close to invisible. The behavior I’d prefer would be for it to stay static (like it was on the GUI I guess). Is that possible w/o having to completely going to the GUI node?

The GUI node was built for this.

To center the quad (that is what you are displaying the texture on?), offset it by negative half its width in x and y axis.

You can also just call center() on the geometry