Wiring a fan to a 3 wire switch off wiring question

So, I recently moved into a house with some old fabric like covered wiring. In attempting to put in a fan I have a switch wired to control a plug on a 20a circuit. The weird part is I have a red, a black and a yellow wire. I’m used to standard 12/2 Romex but am unsure how to proceed. So questions are…

1. What type of wire do I need to buy to run from a new junction box I will place in the attic?
2. I will wire the fan and light together so the finished product will have the blue wire tied in but without a white wire I am not sure how to wire the fan.

Thanks in advance for all your help. If it’s at all helpful I included a pick of the switch that I’m trying to tap into.