Before you can find a project manager, you need to define exactly what your portions of your projects need to be managed and how. I'm sure you know what your projects bring in, money wise, but do you know how many paid hours they can provide towards the pay for a manger AND still provide you with the supplemental income you want to retain? Once you know that, you are in a better postion to give an accurate job description and income offer.
You may have figured all this out, but it wasn't in the post. A few more details could attract more targeted resources or even a project manager directly from WF members or a WF member connection.