1. Cleaned up the background with a soft brush
2. Adjusted the levels
3. Added a lens flare set to Screen for the glow of the lamp
4. Added a hue adjustment layer to the glow to make the light more yellow
You know, 'Just clean the background and place the render in a green background the effects and treatment I want do myself, please.' would give you more chance to have a member doing what you are asking for.
I'm sure there's a corresponding word in the Portugese language you would use when asking a favor.
By the way, what you are asking has nothing to do with 'rendering'. It is simply separating an object from his background.