I had a 3.4 from a state college (I wouldnt even consider it any tier). Although I had an advantage in that I went to an extremely unique school and an unusual major. I was accepted to a top 5 school, so its definitely possible.
The quality of your UG is not going to be as important as your post school work experience. Generally you want a minimum of two years, I would say 3 or 4 with good progression would make your chances a lot better. Besides applications are way up these days, in 3-4 years they could drop back to where they were a few years ago which would make things much easier.
Kellogg Class of 2010...still active and willing to help. However, I do not do profile reviews, don't offer predictions on chances and am far to busy to review essays, so save the energy of writing me a PM seeking help for these. If I don't respond to a PM that is not one of the previously mentioned trash can destined messages, please don't take it personally I get so many messages I have a hard to responding to most. The more interesting, compelling, or humorous you message the more likely I am to respond.