What should I add to my drum kit?

I'm 13 and have been playing for 3 years. I'm thinking of adding on to my current kit, my current kit is a five piece Mapex, with Paiste ride, high-hat and crash. What do you think I should add to my kit? I am someone who likes MCR, Sum 41, 30 seconds to mars, the killers and bands like that. Thank you :)