What you want here, my friend is a "Side-View Battle System".
Your best choice would be to go for Rye's CBS Starter Pack. It has brilliant features and instantly turns your character sprite into a battler!
If you're willing to go a bit more advanced, try Minkoff's Animated Battlers. It requires a little more effort, and there are few recources around, but if you're willing or have somebody on a team who is willing, it really makes your game look cracking.
Hope I could help!