Help with face alignment

Geoff, I need suggestions to help get my putter face square. Here is my problem;

The ball never seems to roll where I am stroking. I bought a laser device that hooks to my putter to show where I am aiming. At address I am aimed at the hole but in the back stoke the putter face swings open than remains open in the follow-through. Even when I take it straight back keeping the face square it still wants to swing open in the follow-through. On a 10 foot putt my putter face is aimed approx. 6 inches to the right of the target at impact.

I'm open to any suggestions you have to help get my putter face square for impact.

Thanks