What to do about this tough financial decision?

I bought a car 8 months ago that I can no longer afford partly because it gets really bad gas mileage and I drive a lot. I’m upside down on the loan. The only way out I see is to get a personal loan from the bank to pay off the negative equity in the car and trade it in for something cheaper and better on gas. If I do this I’ll be paying off the negative equity for 2 years to the bank, plus the new car loan for 5 years. These combined will be more than what I pay now for the car I have. But in the summer when gas prices go up I’m gonna get screwed. Last September I paid 481$ just for gas for the month! Anyway, I found a really good deal on a new Honda Civic. What should I do? Get the loan and the new car or stick with what I have until I pay it off but get killed when gas goes up?