We aren't going to create a new sun (although I like the idea) because the Earth will be blown to pieces by then, we will eventually leave the planet on a massive ark or as I like to call it - ARCK. It will be a massive space ship containing all the best scientists in the world, world leaders, the best and fittest women and men (sexy people too) and a whole bunch of animals, hopefully every single species, plants too, they will take all the best stuff with them and move to a new planet, with a sun nearby and the planet they move to will have to be similar to earth, or as close to earths atmosphere.
The possibilities of finding such planet will not be hard for our future generations as technology and science progresses.
And the building of a massive spacecraft able to house millions of space travellers shouldn't be hard for them either. I'm talking like a billion years from now.