Outlet wiring

In order to do that, you need to have two hot feeds to the outlet, one that is always on, the other from the light switch. This means you need four wires (typically white, black, red, and a bare ground) instead of three. Do you have that today and are just not using the red?

Either way, you can do this yourself, but you might have to fish wire through the walls which may be more hassle than you are willing to do.