The end of MESSENGER's mission, What happens after March 2013? Options

[Seryddwr]

I know nothing about either the technological constraints or the funding possibilities, but I was wondering if anyone knew what might happen to the probe once the extended mission at Mercury comes to an end. Is it definitely going to be decommissioned? Or is there a chance of sending it somewhere else? Is there sufficient propellant to allow it to break orbit using the LVA, and (say) conduct a flyby of an Aten or Apollo asteroid? I do not know how much delta-v would be required to do this, or even if there are any targets in favourable positions, but it would (to my untrained eye) be an excellent reuse of what has proven itself to be a very capable spacecraft.