The Asymmetric Dress was designed with short sleeves, but its doesn't take much to lengthen them, here's how.
Take the sleeve part of your pattern, you will notice that the sides are parallel. To lengthen simply continue the line down to you're desired length.
For the sample made for our magazine photo-shoot we extended the sleeve by 12"/30 cm.
Remember the lengthened pattern piece needs to include the cuff.
If in doubt cut your sleeve slightly longer and then shorten once you've tried it on.
For the fabric quantities add an additional half a yard or 50 cm for the sleeves.