Kennel cough can be hard to resolve and may require a second round of medication. I suggest that you do have her seen as they may be able to give a medication to help break up any congestion ie: a cough medicine.
For tonight you can steam up the shower and take her in. The steam should help relieve the congestion and help her breathe easier. you can also ask the Vet about doing Pecusiion therapy to help break up any congestion. You can watch a video about that here: http://www.youtube.com/watch?v=hrTqco9_jiE
Hope your girl feels better soon!