That sounds sensible, Nettie. Toyota is working towards hybrid versions of its whole line, so you should have some choices. The advantage in gas mileage is most pronounced in city driving, but even highway mileage is somewhat better. The little CT, sold as a Toyota in most of the world, will give you the highest MPG, but it really does feel more like a Toyota than a Lexus. The ES300h is the hybrid version of your car, with the proven drivetrain of the Camry hybrid. It does lose space at the front of the trunk, but that and the higher price are the only major negatives.
When you do decide to buy, I’m sure they’ll still be available. The ES is one of Lexus’s best sellers and doesn’t cost much to develop from the Camry.