2003 Chevy Tahoe Power Steering difficulties

At low speeds or a stop, my 2003 Tahoe is difficult to turn to the right. Turning to the left is normal (easy). I have checked tire pressure and Power Steering fluid level, even added a little just in case. The fluid level remained where it was and there is no fluid on the garage floor.
I called a couple of shops and they would not commit to anything but one guessed replacing rack and pinion and one guessed power steering pump. Are there any interim steps to try? What do you think it is and is the repair job able to be done by an average layman mechanic (me)?

Thanks for your help.