D.F.
Hi J.,
This sounds like it will be really beautiful. You should definitely try the internet and think of some nice restaurants that you think she'll like. Many restaurants have an area/room that they use for events like this. I hope you have enough time to save money, because some places can be a bit costly. One place that I love is Marcello/Father and Sons Pizza. It is on North Avenue near Clybourn, they have a beautiful place that they rent out.
Have a wonderful Valentine's weekend!