The best lens for EOS Rebel T3?

I have recently bought a new DSLR, a Canon EOS Rebel T3. I have looked at a few other options other than Canon, as the standard 18-55mm lens it came with is not impressive at all. I'm not really solid at touching up photos yet, nor do I have photoshop installed on my current laptop, so anything that would render colors a little more accurately would be nice. The cameras come out a little faded/washed out with this lens. The detail is pretty nice and the manual focus works pretty well, but the speed when stabilizer is on and AF is terrible. It's my fault for being a sort of a novice, but I'll learn in time.

I like taking macro shots mostly, such as smaller things like bugs, spiders, text, and the smaller details of things. What kind of lens' do you all recommend and are brands like Sigma a good buy for it?