[Docrwm]

You're getting a lot of intense advice, most of which is probably too much technical material.

Your lens doesn't let in enough light for indoor events with moving objects. That's the "f" rating of the lens. You need to stick with AutoFocus lenses (Marked "AF" usually) as a newcomer to dSLRs.

You need a lens with a smaller (lower number) f like one that is f2.8. There are a lot of zooms that are in that range. Try finding a 28-70 f2.8 lens. Tamron makes one that is well thought of. The lower f will mean that your camera has more light to work with and can shoot at faster shutter speeds. It won't hurt to have the extra reach (your 18-55 is 15mm shorter than the 28-70 so you'll be able to get closer closeups with the 28-70 and get more light).

On changing cameras - wait. Lenses are things we tend to keep, camera bodies come and go. The one you have is old but may well work for you with a faster lens.

Good Luck.

[eddie1960]

I'm with Doc lets get it back to simple since you are a novice. your lens is not letting in enough light, which could be fixed somewhat by bumping the iso up to a higher number but that will be at the expense of noise in the shot, possibly more than is acceptable to you. Ideally you need a faster (ie as doc said smaller number F stop) lens.
If you only need a little more reach to get the shot you want the tamron 18-75 2.8 would be an excellent and affordable choice. if you feel you need to get in even closer (more reach) then maybe get the Tamron 70-200 2.8. the main issue here though may well be at 70 it will frequently be to long. in any case the 28-75 is probably a better starter good zoom, you can always crop a little for the framing later and at 28 it will be wide enough for many situations, you can always add the 70-200 later
As for the camera thing, like doc said wait. lenses are a good investment, you keep them for a long time if they are good. Camera bodies all have one thing in common they are always replaced by a terr model and they always go down in price for the features. better to build your skills first and your basic lens kit (say within tamron the 10-24,28-70 and 70 200 - all good lenses all affordable) then move up on the body to one that meets your budget and needs.

[itsthatflo]

This thread helped, thanks!