First of all, this is a kinda strange place to ask this question... the forum is largely dominated by individuals who have very little grasp of economics, financial investment, or for that matter... hybrid cars... I woudl guess that 80% of them can't even drive (legally).
anyway...
Whatever you do, don't buy a new car. New cars are near the worst investment one can make. You'll lose more money buying a new hybrid than you would if gas prices were still high and you drove an SUV. Depreciation is a *****.
That being said, don't just consider fuel costs when looking at hybrid options. Consider the time investment of stopping at the gas station more often if you don't have a hybrid, and things like that.
Also, consider that in a number of years, your hybrid's electrical components will need replaced... which right now, is somewhat costly (but currently unneeded).
Honestly, if I had to make a call from here in my computer chair... evaluate how much you drive... compare the savings in gas to the cost of your next car... and the interest that you'll be paying each month and each payment...
Balance it out. Whichever one leaves you with more $, go for it.