For some reason I feel like I'm having this discussion in two places at once
For romantic plus something to do afterwards in walking distance, I'd go to Hemmingways and then take in a movie at the Lake theater--about a block less than half a mile away. An alternative stroll would be down Oak Park Avenue, particularly to show off Val's Halla Records.
But the Forest Park business district is much more interesting overall, and La Piazza would fit your plan well unless you think a movie is the way to go.
If you haven't been to Fitzgeralds', however, you owe yourself the treat. Check out
http://www.fitzgeraldsnightclub.com/
You could eat there, of course, in their new restaurant. It's not terrible, by any means.
But if it's a romantic restaurant you want with great food, go to Hemmingways.