TS, you have to ask yourself really hard. What are you shooting? People in the streets? abstract? Buildings? The body is just a body. Any camera body can shooting anything. But you have to choose the right lens to do the right job. Same goes for your style in photography.
Your D3000 can definitely do the job. But we need understand more about your style or genre in photography. example, current equipment, scenery? which kind? people? which kind? Might be a nag but you know, just trying not to lead you to a wrong path.