My Rebel sucks. I suck. Should I upgrade?

I had 400D and I really disliked it. My cam was front focusing, overexposing and it took a lot of post processing work to make pictures look good, even outside of AF and exposure issues. IMO you have good glass deserving better camera and I kindly disagree with other posters, DSLR should have better  picture quality than P&S even in full auto and most do. New, better camera won't make you automatically a better photographer, but at least you can concentrate on composition and artistic side of picture taking, instead of constantly fighting miss exposure, miss focus etc. The sample you posted means little, even best camera will miss some shots, it's the overall results that count and if you say most pictures look bad, I don't think it's your lenses.