Add combo (switch and outlet) with only two wires out of wall for the current light)
Your first diagram shows a switch loop. 

Neutral and hot wires arrive at the light box, the neutral stays in that box, while only the hot is sent to the switch box (customary using white with black marking), and returns with the (customary) black wire, which is now a "switched hot".

If you want an outlet at the switch box, you need to bring a neutral from the light box. A customary way would be to wire a 14/3 or 12/3 from the light box to the switch box:
- white neutral
- black hot
- red switched hot (returns from the switch and connects to the light fixture black).

You can then decide wether you want this outlet to be always hot, or if you want the outlet to be switched.

The wire gauge depends on the breaker size. 15A breaker requires 14 gauge or bigger. 20A breaker requires 12 gouger bigger.