What is the best zoom lens for an indoor concert?

I am attending a Keith Urban concert at Philips Arena in June this year. I am planning on taking photos with my Canon Rebel XTI / 400D. The only lens I have now is the EF-S 18-55mm lens that came with the camera. I have been looking into buying a good zoom lens for the past few mos. & I've decided I definitely want to purchase one before the concert. I've been researching the Canon EF 70-300mm f4-f5.6 IS USM lens for some time now and think that it is appropriate for my needs. What can I expect with this lens from a distance of around 250-270 ft with low light, although I expect the stage to be well lit. I will not be using my flash. I want a lens that will zoom in enough to get good close up photos. I have included a link of a 3D view from our seats if you'd like a better idea of how far. I'm not the best at determining distances. If this lens is not good for this kind of photo, what would you recommend? Serious replies only, don't tell me to take a point&shoot. I am taking a point&shoot camera but I don't plan on taking the close up photos with it. And also, I have already spoke with reps from Philips Arena and my camera is allowed.

http://www.seats3d.com/mv/philips_arena/stage_end_...