At your level, Gaara (3 star) and kyuubi Naruto (2 star) are enough for you to get things done in game like survival, story and elite instance and ninja exam. For the ninja you want to add, pick Tenten GNW if you may, she can add crit to entire party for 3 turns, aoe and still usefull at high level team (level 90). BTW Gaara is a tank so you can put him in the front along side Naruto.

TLDR ver : Get 1010 GNW, level up some moar ;p