Like Atrevida said, also try posting something here, you never know if someone in the group wont be able to make it to the concert and is looking to sell there tickets. If you have no luck with that than the only thing left is Ticketmaster.
I know you live in Chicago and well it's not impossible, Gabby made it to Jenni's concert at the Gibson almost 2 years ago, and she came all the way from Chicago for that.