First of all, I would say that your 07 Rondo still probably has a fair bit of life left, unless you know of a specific problem. If you look at the repair data on this site, the 07-10 Rondos are all in the 44-70 repairs per 100 vehicles per year territory, and not many of the reported repairs are super expensive; sensors, steering components, brake components; the usual suspects. You'll be able to keep driving the Rondo for less money per year than even the most reliable $9k car you could replace it with; at least for a few more years.
If you do go the "replace" route, the Honda Fit is a smaller car than the Rondo with good interior space. If it fits your people+stuff, it will be your most economical option.
Vehicles similar to the Rondo that you might want to consider would be the Mazda CX-5, the Mazda 5, Honda CR-V or Toyota Rav 4. Another Rondo isn't a terrible idea either if you like it.