[aedon]

I had a semi similar issue.
I ordered mine off ebay and it had some scratches ono the digitizer.

I ended up ordering a new digitizer from ebay

replacing it isnt impossible in the slightest. its just alot of work and take alot of pre planning and knowlage

I got a digitizer (glass screen and the plastic digitizer) for about 20 bucks.

but your right, there are 3 layers.
Bottom is LCD. it consist of a few layers of very thin film sheets that bend the lights to produce the image.

Then the glass screen. this protects the lcd

and then the digitizer, wich hovers a few milimerters above the glass.
the reason for that is because when you press down on the digitizer, it registers the center of where your pressing to tell the phone where your touching.

Now... again I will stress it is ALOT of work. I highly suggest doing research lol

If you have any questions feel free to ask.