What is your definition of "nice" and "break the bank?" There are a ton of great restaurants downtown and just north of the river - though I think the ones I want to recommend will fall into the break the bank category (i.e. Le Lan). I just checked opentable and most of the restaurants that take online reservations in that area have availability for around 5:30 Friday (which I am guessing if your target time if you have to be at Union station for the 8:00 train). And while Water Tower Place will be busy, you can always go to Foodlife for a decent meal selection and place to sit.