loose junction box

I want to install new lights in the ceiling. There are electrical points close to the floor and I would like to avoid installing a new circuit. I have not done this before and would probably need step by step direction. I would appreciate all the help. Thanks

I have a few questions. #1) I need to put a receptacle next to a switch that feeds an out side light. I believe the power comes into the switch and up to the light. There are two black wires on the switch and the white wires are connected together. ( there is only one set of wires going to the light) What do i need to do to get power to the receptacle? #2) I also need to put a receptacle next to a switch in a bathroom. I believe th power comes from the light down to the switch. ( only one set of wires at the switch) is it possible for me to power an outlet under these circumstances? If not what are my options? #3) Do all outlets outside need to be GFI? #4) last one . I have 3 outlets on my kitchen counter with no Gfi. How do i determine which outlet the power is coming into so I can put my GFI there? Thanks