re: "more zoom" and "lower light ...concert"
The best compromise is probably a Panasonic FZ200: it's got a 24X zoom and a relatively fast/bright constant f2.8 lens. However, note that it's on a large side for a point-and-shoot, so it may be classified as a "professional" camera by concert security (even though it's not a DSLR). It also costs around $600.
For something smaller that probably will be allowed in by concert security, you will have to go with less zoom--probably much less, like not even use the zoom at all, which means you'll need to be in the first few rows to get good pics--like a Sony RX100 (which costs around $700) or a Canon S110 (which costs around $400).
HTH - Mark