You came in last because you don't have a very good team. You're starters (assuming a 1QB, 2 RB, 2 WR, 1 TE, 1K, 1 DEF setup) look like:
But wait, there is help! Drop Daniel Graham and pick up Stacey Mack. He'll back you up if Taylor gets hurt (very possible). Lamar Smith has to go. You can pick up DeShawn Foster in a couple of weeks, but he's just a burden on your squad right now. Gadsden will not help you all that much. There have to be better fantasy players on the free agent list. Oronde is a good football player, but not a good fantasy player when he's the #2 WR on a run first team.
The big move I would try to do is trade McNabb for a solid runningback. Try to get Eddie George, Travis Henry, Ricky Williams, etc. You can pick up Shane Matthews, Brad Johnson, Drew Brees or someone like from free agency. Bledsoe will be a good QB this year with good weapons around him.
Portis is also not a good fantasy pick because of the rotation in Denver.