Try taking some classes this summer, the more you can show them that you can are committed to making good grades, the better. Write a compelling statement of purpose with your application, and make sure whatever essays you write are proofread thoroughly, since you have no margin for error this time around. If I were you, I wouldn't even try for McCombs right now, and you can always try to do an internal transfer like other people were saying. If make it into UT, but you don't end up making it into McCombs, you can do something called Business Foundations, which is a certificate given through McCombs and is basically a business minor. Anybody can do Business Foundations.

My transfer was easy since I lived close by, and the application isn't too hard either. You can look up how to make a good college application resumé online, and don't leave anything out of it. Anything that could be considered in your favor should be included, no matter how small.