Many will tell you that lenses are more important than the body, so if I were you I would try and get some lenses. In my opinion a 17-55 f/2.8 IS together with a 70-200 f/4 IS make a great set for a crop frame camera, but they don't come cheap (some 2200 USD for a set of brand new ones, don't know how much cheaper you could get them used).
Think about it, some choose the way of buying what they can afford at the moment, and some prefer to make a wishlist and save untill they can afford the stuff they really want, both ways are good, and ... in the future you can always sell some lenses and get other ones.
Also I don't know about the quality of the pictures taken with your tamron, but if you're happy with it, don't bother with the canon 17-55, just go for a Canon 70-200 f/2.8 IS (1900 USD new), or f/4 IS and some primes.