Help with replacing wall outlets

So my house was built in the late 50s. All my outlets are 2 prong. I am going to switch to 3 prong. My outlets are in metal boxes and there is copper wire that looks like its coming from both the hot and neutral wires. How do I ground the 3 prong and what do I do with this copper wire? I attached a photo of what I mean, thank you.

 

I was able to post the pic

 

Easiest is to use the short green "pigtail" wires available at the homecenter that have a spade lug on one end and a ring lug or bare wire on the other end. You would connect one end to the grounding terminal of the receptacle and the other end of the wire would go under the screw also holding the bare wires.

You could also buy a length of #12 or #14 green-insulated wire and make your own pigtails. You don't need the lugs if you use solid wire. Use either #12 or #14 to match the gauge wire of the power wiring. Best to then wire-nut ALL the grounding conductors and leave a "tail" to connect to the box.

 

You have a black, white and ground all you have to do is put wires on screw terminals and extend ground to ground screw on new outlet. Do not use the back stabs.

 

All the grounds need to be spliced together and also connect to the receptacle.