Do a kfb/pfb increase on the end st, then just add 1 to the rib pattern. At the beg of the row, kfb, k1, p2, k2, etc, ending with k2, p1, pfb. On the next row you'd start p1, k2, p2, k2, p2 and end with k2, p1. Knit the knits and purl the purl sts as you come to them on the following rows. On the next increase row, start with pfb, p1, k2, p2 and end with k2, p2, kfb. Then on the next and following rows you'd have enough sts for 2x2 rib again. Learn what a knit and purl st looks like, just add the new sts at the ends of the rows (where how you make them will be hidden by the seam) and keep adding them to the pattern.