No design needed.
I have created 2 pages almost identical (background and colours change) in a simple design using PhotoShop (in layers,) all you need to do is convert it to HTML and integrate it to the existing site, however having an eye for design would help, just in case I have missed something, it would help if you could spot it ...lol
Your coding needs to be perfect for this job to complete.
At this point there are NO errors or problems on the site, and needs to stay that way :-)
Start as soon as possible.