Whoa wait.

You get 171.4 more miles per tank.

At 50 miles per gallon instead of 38, you're saving about $9 per fill up, not $26. So if the hybrid is $6640 more than the normal Civic, you'll need to fill up 738 times before you see savings.

738 times is just shy of 500,000 miles. (your $26 calculation seems to be dividing by $2, not by 38 mpg)

Also, try taking a hybrid to a repair shop. Sure, your warranty is great, for a few years. But even in 5 years, how many shops will be working on hybrids? Not many, if there aren't a LOT more of them produced.
The profitability just won't be there. Why train or pay mechanics that are hybrid certified, assuming there is a more than negligible increase in pay? So why would anyone GET certified if there is only a negligible increase?

My suggestion: Buy a regular Civic, keep it well-maintained, and you'll still be driving a very fuel-efficient car.