I was looking this up because I had gotten my hair done a week ago and I wanted it to last more than a month, and the answer is you can use ammonia-free semi-permanent hair color. To get long lasting color I use sulphate and silicone free shampoo and conditioners.
A good choice. I use special shampoos and conditioners for color-treated hair and it helps to prolong the color.
I use sulphate free shampoo and hair mask. It does really help!