Newbie help

Heres what I want to do in Photoshop elements. and I hope you learned chaps can help me. I have an old slide thats been found of my late grandfather, but the slide has been damaged over one of his eyes, I have scanned this slide into my PC and would like to copy an area around the good eye, mirror image it and paste it over the damged eye , SO i have used the QUICK SLECTION TOOL which selects an area around the eye, but it wont allow me to COPY the area then paste......Can anyone offer any more advice....:confused:

after made a selection of the good eye,
still with use of your selections tool, click right ...and select in the pop-up menu... copy to new layer.

this new layer you could use and move to the other eye

Right clicking gives me three layer options, Layer via copy,Layer via cut and new layer......which should i choose, and then what do i do with it , I apologise for my lack of knowledge