You're going to find this a pretty expensive hobby. I won't go into longer telephoto lens since you just talked about indoors. Yes, the kit lens is good, but it's not a good low light/indoors lens. You have two options, you can buy another lens in that same focal length, that also has image stabilization, and a large aperture(F2.8) but that will cost you as much as the T2i alone. The other option is buying an external flash, which will still run you $220 or more, depending on how much power you want.

The video part, I'd say to get a tripod, especially with the low light areas. If you don't plan on needing a lighter tripod then you could probably get a decent one for under $100.