What canon dslr should i buy?

I have a canon rebel xsi.. ive looked at the canon t2i, and the canon t3i is no different really.. I really like the t2i, but someone has suggested the 7d for me. It seems very difficult for my age. I'm really into photography and I'd like to use it as a side career one day. the 7D is expensive, but not as expensive as the 5d mark ii. I only have $900.00 but i'm willing to wait and save.. so it's the 7D with no money left (but a good camera indeed) or the t2i with accessories. I have some lens and a camera bag already and a tripod.. any other body suggestions?