Yasick, your images can be much better if you learn some post processing techniques of first cleaning up the noise, then work on the rest of the image. Get the exposure correct or even to the right more in-camera makes a difference, than if you just move exposure sliders around during post.
The 7D does well enough at ISO 6400 for low light events, it would be a major improvement over the 30D in all ways except 100% crop sharpness checking, however, the 7D has a huge resolution upgrade over the 30D, so resizing down to 8mpx would get that back. However based on what is being described as the goal, I don't see where the 7D provides any advantages over a FF and would even consider a 5D2.
ISO 12800 out of camera, no post, 7D