Don't get too excited over Gallups approval. It's highly suspect due to increased non white voter percent. A 6.6% increase over the record 2008 level (and 4.9% jump week-over-week). So if you belive that'll happen this election by all means enjoy Gallup's poll.
End of september the % of non white vote was 25.7% in Gallup's poll and in September overall had averaged right around 27%. October they jumped it up to 30.6%.
In 1996 non-white voters were 17%, in 2000 20%, in 2004 23% and in 2008 26%. So this result seem to keep up with a long-term trend.