I think an approval rating for President Obama of 54-56% at a time when unemployment is 10.2% is pretty good and proves that many people do understand that Obama inherited this problem and didn't create it. He still has good will.
Now I can see as time goes by and if unemployment remains stubbornly high for a year or so that Obama could move downward in his approval but just remember the presidential election is three years off and that is ten lifetimes in politics.
Look at where St. Ronnie was in January, 1983 (two years into his term) and remember that in November 1984 he was re-elected with 59% of the vote (per Gallup):
Indeed, although 1983 began for Reagan with a 35% job approval rating -- the worst of his administration -- things started to look better.
His ratings moved back above 50% by November 1983 -- not only because the economy was picking up, but also in part as a result of rally effects associated with the U.S. invasion of Grenada and the terrorist explosion that killed 241 American Marines in Beirut, Lebanon.
By 1984, Reagan's job approval ratings were consistently above the 50% line that is a symbolic standard for an incumbent president seeking re-election. In Gallup's last October poll before the November 1984 election, Reagan received a 58% job approval rating, and he went on to soundly defeat Democratic nominee Walter Mondale by a 59% to 41% popular vote margin, receiving 525 electoral votes to Mondale's 13.
http://www.gallup.com/poll/11887/ronald-reagan-from-peoples-perspective-gallup-poll-review.aspx