The T2i is a slightly better camera than the T3 but they're so close that you won't notice. However, the T3 is also only slightly better than the Xt.
If you can't afford to spend much then I'd suggest trying to upgrade lenses on your Xt first. For instance, the EF 50mm f/1.8 lens is a very affordable choice and will allow you to shoot in lower light than you would be able to with your kit lens.


