Yes, it would fit. Don't get the Antec VP, get an Antec Neo Eco (either 400, 520, or 620). I have the 400C which is a great deal at 50 bucks: http://www.newegg.com/Product/Product.aspx?Item=N82E16817371029. Plus it saves you some power with the 80-plus efficiency
400w doesn't sound like a lot, but on a high quality unit its fine. I'm running a 95w TDP Core 2 Quad and an HD 6850 on it, but use more power than your CPU and GPU. If you think in the future you will want a great GPU, get the 520C, it has 2 PEG connectors for graphics.