Hi, Do you have any other lens besides your kit lens?
If you do not have another, I would suggest getting a fast lens like the Sigma 18-50 f2.8 DC EX HSM first. There will always a better body to come any way, so what's the hurry in upgrading your camera body now?
On the othet hand, you find some other limitations on your camera body, then going to a new body would work too, but I seriously doubt you have hit the limit of the body yet, but lenses' limit if you are just having the kit lens now.