I've seen Missouri swing back and forth in past races, so I'm not sure it's a given that they will vote Republican. Until 2008, Missouri had voted for the winning candidate over the past several elections. Chances are there will be enough white conservative Americans to swing the state toward Romney, but I wouldn't consider it a solid pick. Still, the vote tends to be conservative.
I think your map above is a close prediction of the outcome, except that I believe Colorado and Virginia could both wind up being democratic as well. Even if both states sway to the Republican side, I don't see Pennsylvania doing so.
Based on those predictions, I could see President Obama winning by just about five to six percent of the popular vote, or somewhere between 291 electoral votes and 302 electoral votes.