Wharton professor and author Jeremy Siegel says he thinks the improving housing market will push the economy higher in 2013, with the improvement accelerating as the year goes on. Siegel tells Bloomberg that increased sentiment because of gains in home prices should lead to increased consumer spending. He still thinks we will see the Dow Jones Industrial Average hit 15,000 by year-and. Siegel says he doesn’t think the recent increase in gas prices or the increase in the payroll tax this year will be enough to stall the consumer or the stock market.