That is a good question but I have no idea. By definition they will not stop printing money until conditions have improved. They aren't made that way. Their jobs are to fix things right? Then they will have to fix something else even bigger.
http://research.stlouisfed.org/fred2/series/BASE I think they've done enough money printing for a while, but seriously we need to print more and get the economy moving again if we are to have a hope of getting out of this mess. The tradeoff is unfortunately (For those who like cash) higher prices in the future. Buy your gold. Personally if they combined all of this money printing with an aggressive nuclear energy + electric car policy (which would partially deflationary actually), I think we could create so much a wider margin in disposal income going forward that could fuel an investment boom in the future that would make our past debts a non issue. (as they would be devalued anyway)