New camera body versus new lens for old camera?

I use a sony a200, its kinda old 2008 or 2009 model, 10.2 MP. If i was to upgrade to a nikon d7000 or a 18 MP DSLR, will it improve my pictures or will it just add more features/buttons. Or would upgrading from a 55mm macro lens to a telephoto or standard lens be a better choice?

Camera bodies aren't terribly important. Going from 10 to 18 megapixels won't really do anything other than allow you to print larger before you end up with a pixelated mess. Also, switching from Sony to Nikon bodies will mean you won't be able to use any of the Sony mount lenses you already own.

Going from a 55mm Macro lens to a telephoto lens or some other lens isn't really an upgrade. The whole point of interchangeable lenses is to have multiple lenses that do different things better than others. If you purchased a 200mm telephoto, for example, it will behave differently than a 55mm Macro. The lenses are designed for different situations. One is better than the other at certain things, but terrible at other things which the other might be good at. Its a trade-off, not an upgrade. You have to decide what you are going to shoot and base your lens selection off of that.

In the end it all depends on what you shoot, and how (or if) you want to expand your photographic horizons.

I think it depends on why you want to upgrade your gear. If you're hitting limits in resolution, low-light ISO performance, AF, or something else that is dependent on the camera body, then upgrading the body makes sense (the D7000 is an excellent camera BTW!). However, if you're reason is a limitation in the lens (DOF, aperture, sharpness, IQ, etc), then the lens would be a better upgrade.

The bottom line is that through practice, the limitations in your current equipment should be driving your upgrade path (and not some stranger on the internet.

I use the Sony A200… And haven't had any problems…

why go from Sony to Nikon? Why not use the existing lenses you have with something like the A65 or A77…

if you are having trouble getting the images you want, are you sure it isn't your skills that are lacking?