Help my hair get healthy?

my hair is flat cut at the bottom and shoulder length and REALLY DRY in the back! i do wash my hair daily because i dont wear it up and it gets greasy very easily. my daily care for it usually is shampoo(tresemme) and conditioner, w/ semi-cold water and drying with blow dryer after about 20 minutes out of the shower. when im done drying it i brush it and put some aussie hair spray. i straighten/curl my hair maybe once a week. does anyone know any GOOD products that will help my hair get healthy so i can grow it long again or what do i do?!?!