Bests in Ithaca?
You may want to try out The Carriage House- intimate space that just adjacent to campus. http://www.carriagehousecafe.com/index.php
For a sample dinner menu (to give you an idea of offerings and pricing): http://www.allmenus.com/ny/ithaca/255183-carriage-house-cafe/menu/
Depending on what kind of dinner it is, you'll probably want to check whether they have live music there on your special evening(s).
Or you can get a booth at Madeline's, enjoy dinner, and linger over one of their many wonderful desserts.
Carriage House Cafe
305 Stewart Ave, Ithaca, NY 14850