Since it's the last row of ribbing, just add the stitches and work the rib stitches as they've been all along. Knit the knits and purl the purls. At a quick glance it looks like your increases are on knit stitches, so just kfb in those stitches and purl the next.
The best advice I can give on the cable pattern is to use markers on your needles and post-its on your chart to keep track.
Good luck with it!
"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