OT: Need a margarita near California/Diversey

For real!  I found a nice girl who lives near California and Diversey and I finally asked her out.  Wait... it gets better.  When I asked out, she invited me to her place and is going to cook me dinner.  I know, right?

After dinner we're going to go out for a drink - and margaritas are her drink of choice.  She's new to Chicago and I'm new to margaritas.  Where is there a NICE place near her that has great margaritas?