With ribbing, if there is an even number of stitches on the needle, you will k1, p1 to the end of each row.
But if there is an odd number of stitches on the needle, you will k1, p1 to the end of the first row, then p1, k1, p1.. to the end of the next row, then k1, p1... on 3rd row, and p1, k1, p1 ... on 4th row, etc. [COLOR="Magenta"][B]BUT[/B][/COLOR] don't worry about trying to figure that out!!! Its second nature once you've been knitting a while but too confusing when you're starting.
Just learn what a knit stitch looks like and what a purl stitch looks like. Then on each new row when you rib, you will knit the knit stitches and purl the purl stitches.
If you go to this thread and scroll down till you see Jan's photo of some ribbing, take a look at the way the knit and the purl stitches look. Her's is wider ribbing with 4 knits, 4 purls, whereas your's should end up as 1 knit, 1 purl, but the appearance of the stitches is what will help you. When you see a V in your stitches, you knit the stitch that's on the needle above it; when you see one of the rounded shapes, its a purl, so you purl the stitch on the needle above it.
Oh, and as Rosefairy pointed out, when moving the yarn from front to back or from back to front of the needles, move it BETWEEN the needles, not under them or over the top. Just check the number of stitches you have at the end of each row for a while, to make sure you don't have more than you started with.