What you're asking for is a hypothethical with little practical sense. I say that because the level of which he'd need to alter his views to be able to get me to be able to support voting for him in 2012 would be SIGNIFICANTLY raised due to his actions over the past 18 months.
If you had asked this question 36 months ago it would've been simpler. Give me a candidate on the Republican side I'm not hot on, with a legitimate reason to believe Obama is going to attempt to be relatively moderate on most issues, not push any extremely strong liberal agendas, and legitimately work towards REAL bipartisanship where both sides ideas are attempted to be equally represented allowing new ideas fo flourish. I would say that could've gotten my vote for Obama in such a situation, as he's a likable and charismatic figure whose election I could have seen doing good things for the country while his policies were of such that were either verging from bareable to agreeable.
However, asking it of me now, there's little he can really realistically do. At this point he's moved so far to the left on certain issues, has done actions that have so angered and turned me off, that simply a shift to moderate would not actually do anything for me. Cap and Trade, the buying out of industries, the health care plan, the method in which TARP is being executed, his conflicting foreign policy with his foriegn presentation, his lies about being a change to politics as usual, his misrepresentation of post partisanship, his continued and pendemic desire to pass the buck, etc. At this point, due to no actions other than his own, it would take a complete and utter 180 for him to get near my vote.