My College Wardrobe Needs Some Serious Updating

I just graduated from college, and I've spent the past four years wearing an everyday style of jeans, t-shirts and flip-flops.  Now that I'm done with that undergraduate phase of my life, I need a new, professional wardrobe for work, and a casual wardrobe that includes pieces other than torn, stained, sorority t-shirts.  How do I get myself on "What Not To Wear" so I can afford the wardrobe I need?