You could add some ribbing to the bottom. This will add length and get rid of the curl.
If you wanted to add more pattern, I'd probably knit it on rather than sew it on by picking up stitches. You'd add a seam, but it wouldn't be all that noticeable. Also, you could add a hem for the curling if you went that route.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry