Question: how to do a yarn over between a knit and purl stitch?
Answer: Knit the first stitch.
Bring the yarn to the front into the purl position, wrap it back over the top of the RH needle, and return it to the front into purl position again. Basically you're just wrapping the yarn once around the RH needle from the front.
Purl the next stitch (see the following figure).