What will you be shooting, mainly? You'll have to sacrifice somehwere. Did you get the kit lens? Its an EF-S 18-55. 
 
IMO, I would look into two cheap(er) lenses. One a 70-200 (or 70-300), and either a lower telephoto, or a 50mm prime.  
 
The classic is the 50 f/1.8, what can be had for about $75, but that is if you don't mind a prime. 
 
Using about the same budget, I picked up a Sigma 70-300, and a Sigma 28-70. I am happy with them, considering what I paid. 
 
Of course, what you get, will depend on what you shoot.