Need shampoo advice!

Okay so I need some shampoo advice. Whenever I color my hair, it tends to turn red after a while. A friend of mine said I should be careful what shampoo I use. Got any suggestions?
After much trial and tribulation, I have gotten my hair pretty close to it's natural color, this is so I can stop coloring it actually.
So it's what all my life I thought was a drab ash brown, just plain old brown. Nothing exciting. Wella med ash brown and light drab brown. I put a few highlights in it, very small ones, which I took from a photograph of me when I was 15.
But I really like it oddly enough, my BF is nuts for it, he keeps looking at me funny, my best friend says I look like I just grow gorgeous hair, I really love it and want it to stay this way.

 If you need a great shampoo that will keep color in use the Matrix Color.smart, it's design to keep color in, you can get it at any JCPenney's or Mastercuts, Regis, those sorts of places.

 I agree with the other post that you should always use an Ash based color line and only 20vol peroxide as that will give you the least red result.

 Don't wash your hair for 2 days after you first color it, that way the color tends to stay in better.