How do I wire a switch/receptacle combination?
Yes, that is correct.

Another alternative is to disconnect the existing supply, and run a new line to the switch/receptacle. It really just depends on which line is easier to run.



(Note, I just copied the original image, but didn't erase the ground. The ground should be connected to the box and the ground nut on the receptacle, and switch if it has one. At no point here should the ground be connected to neutral, or anything but a box or a ground screw. Thanks @Skaperen)

You should disconnect the other wire though, at both ends, and connect the conductors together so if anyone mistakenly energizes that line in the future, it will blow the breaker.