What should i do?d7000 or d90? or new lens?

i have the nikon d5000 right now and im not very happy with the quality of pictures and especially video, i have the Nikon 18-200mm f/3.5-5.6G ED AF-S DX Zoom-Nikkor Lens on it right now, the quality of my pictures is pretty good or okay but i want better then pretty good should i get a better lens if so which one or should i just get a new camera altogether with the same lens i have now?