I use a hair masque, such as Macadamia, it makes my hair very smooth and even a little shiny. It's about $4.00 for a packet that lasts two to three times, well for me, my hair is thick but between chin and shoulder length. It's not recommended to do the masque more than once or twice a week, directions on package.
Matrix makes a conditioning balm which is great! Have you tried Rusk's moist shampoo (I'm pretty sure it is for color treated hair) and following with a conditioner such as Rusk calm or pure or their detangler conditioner.
I try to get a trim every time I get a chemical service such as color or highlights because I don't want my hair to dry out and have split ends.
Maybe consider talking to your stylist or ask in a beauty supply for advice too.
Also iVillage has beauty forums where you can get hair advice.
Good luck.
Amy