Anything can be hypermiled. Since it mostly city Aero won't help that much. I agree with the grill block. Any chance of a getting a scan gauge? That alone could probably hit the target. Route selection is key. Might want to back into the drive way for the quick get a way when the engine is cold. Take a look at the 100+ driving tips. That's where you will get your biggest bank for the buck.
As far as car comparison you'll need to run the numbers to see if getting the Corolla will pay off.
Good Luck and welcome to the site.
