Hi,
I've read photography forums and magazines for many years and I've seen lots and lots of questions like this. Hoping for improvement through buying new kit is always very tempting, I do it myself too, but I'd say that it rarely seems to work very well unless the existing kit is actually inadequate for the job in some way.
In this case, Beth, your kit should already be more than capable of producing excellent pictures quite easily, and if you look around the web you'll probably see loads of great photographs taken with it, so changing it is unlikely to help at all. I suspect that you'd get far better results through taking the time to read up on photography a bit more, practice taking lots of shots and see what works and what doesn't, play with the camera settings and try different shooting modes and so on - there are loads of settings to fiddle with on modern cameras.
Don't get too concerned with technical issues though, there is also the artistic side of photography to consider. You can have lots of fun with composition and finding new ways to look at things even before your shots reach technical brilliance. Which is good, because mine still haven't!
If you would still like to invest in equipment then it may make more sense to get additional things, rather than replacing what you already have. Books are always good if you like reading. You could consider image editing software, too - its seen by many (though not all) as an important part of digital photography, although that too is something that takes time to learn to use for best results. Many photographs can be improved through playing with the brightness, contrast and color saturation in such software, and even more complex adjustments can be made. Though this is an additional step so please don't see it as a magic solution to bad photography.
That said, if you are rich one benefit of buying the best kit available would be to finally prove to yourself that a great camera doesn't make a great photographer - in fact it could even do the opposite, since entry-level cameras tend to offer the beginner more help than pro cameras do. If I could afford it I may be tempted to get a great camera myself, then maybe I'd finally stop wishing for the best kit and spend my efforts more usefully, such as learning to take better pictures!
All just my opinions anyway - in case you find anything useful in them.
Kevin