Do not waste your time.
Take the San Diego Trolley (San Ysidro/Tijuana) line to the last stop and cross the border. Bring passport.
Once over the border say one word to any taxi driver you see: Adelita's. And you can thank me now.
Pick from the 60 or 70 ladies who are there (pay no more than 50 + 12). If nobody there appeals to you, walk out the front door, make two rights and you will find yourself in "The Alley". Here you should pay no more than 20 plus 3-5 for the room, for a short timer. All the surrounding streets are also fair game.
Also, do a search here ("Adelita's") and you will find much more.