First, finish your degree.
Second, work on some sort of programming project. You might make a significant contribution to an open source project -- enough that you can point to code and/or features and say "I did that." Or start your own project and build something useful. It doesn't have to be the best thing in the world, it doesn't have to gain huge popularity. Again, you want something that you can show off and say "here's something significant that I did."
Third, look for jobs where you can leverage the degree that you will have. If you complete a triple major, that's pretty significant in itself. Having skills in math, statistics, and economics will make you desireable in a way that other developers aren't. I'd expect that having a solid knowledge of any one of those fields would be more important than being an expert programmer, and you should be able to use those credentials to help you land a position where you can continue to develop your programming chops.
Fourth, don't rush. Finishing your degree is much more important than landing your first real job. You'll spend the rest of your life working, but after school you're going to have a lot of trouble finding the kind of time and freedom to explore and learn that you you have in school. Take advantage of the time you have now, use it to build up a solid reserve of knowledge that you can draw on for the rest of your career.
Fifth, skip the certifications unless you're going for a particular position that requires one. I've been programming for a long time, and I've never even been asked about any certifications or felt that any would be beneficial. I can see how they might be appealing since your degree isn't in computer science and you don't have any experience, but remember: after you land your first job, you'll have experience, and you only have to find one person out there who's willing to hire you in order to land your first job.