How can i make my acceleration better?

i have a 1997 Acura Integra GS auto tranny. when i first got the car and i would step on the gas it would fly but now its like when i step on the gas it wants to accelerate fast but it wont do it any more like it used to. every time it switches gears the rpm's start off real low and it makes go slow. does anyone know how to make my acceleration better again? is there some fluid that needs to be changed some part that needs to be swapped out?