I'd say about this. Obama wins delegate count and popular vote by small margins, ends up winning the nomination something around 2500 to 2100 delegates or so for Clinton.
In the general against Romney, assuming a similarly strong economy to OTL, I say this:
Romney / Ryan - 312 EV, 50.6% PV
Obama / Warren - 226 EV, 46.8% PV
But if we're going with brucejoel99's scenario of a worsened economy, maybe Eurozone implosion, etc. I'd say this:
Obama / Warren - 348 EV, 51.9% PV
Romney / Ryan - 190 EV, 47.4% PV
Basically OTL 2012 except flip North Carolina and NE-02.