Last night I was looking at dresses online, and I found one on David Bridal's site that I really, really like. However, it's available for order online only, and they don't sell it in stores. It's also on sale for $150 right now which is crazy! The sale goes until the 18th. I'm thinking about ordering the dress because I'm only going to be out on the $15 shipping fee if I'd need to return it. 
Anyway, the problem is I have no idea what size to order. DB has a sizing guide on their site and based on the guide, each of my measurements is a completely different size! My bust is a size 2, my waist is below 0 and my hips are between a 4 and a 6. The sizing guide is below if that would help any... If I do order the dress, I don't know whether to get the size 2 or the size 4.... I'll likely loose another inch from my waist and hips within the next month or so now that I'm not sustaining myself on Christmas fudge and cookies. LOL! 
I also know that no matter what dress I end up with I'll need to have it altered, but I don't know what size would be best for the alterations...or even if I should order it at all since my measurements are so odd.  
Any advice would be very much appreciated. 

Sizing Guide
http://www.davidsbridal.com/webapp/wcs/stores/servlet/popup_dbdetails?storeId=10052&catalogId=10051&categoryId=0&sn=2455&sc=bridal.0_16.SAS&prodgroup=0&dt=fg# Dress
http://www.davidsbridal.com/webapp/wcs/stores/servlet/ProductDisplayView?storeId=10052&catalogId=10051&categoryId=-49976984¤tIdx=31&subCategory=-49998493|-49976995|-49976984&catentryId=2000231&sort=