I just saw this post--since you didn't post again I hope you already found help, but just in case, here's my little bit of advice. Have you tried the sizing calculator at www.Hotslings.com ? Sometimes people will get multiple size possibilities, and it ends up being a matter of preference. I have a friend who is about 3" shorter and weighs about 15lb less who wears the same size as me because her bust is significantly bigger than mine. If the sizing calculator doesn't help, you can also join the Hotslings yahoo group (there is a link from the Hotslings website) and look in the database. People have entered their weights, heights, bra measurements, etc and said which size fits them best.
As for the best deals, I'd say either FSOT here or at TBW.com, or right here at ATB. Angelas prices are good, anyway, but then she has the returns/clearance.
HTH!
Serenity
SAHM to three Army Brats
Jack 7, Ellen 5, Claire 2 (and #4 EDD 10 Mar)