Well, you could take some undergrad classes now at a local school (even a community college, which would be cheaper) to show you can cut it.
Make sure your work experience is more than just decent, though...I had strong undergrad stats but my work experience didn't stand out (neither did my GMAT), and I didn't get in anywhere. Not trying to add any stress here, but make sure you take opps to develop leadership skills and show it at work. It'll help make up for the lower GPA.
And of course, kick butt on the GMAT!!