If you want someone to give you a quote then a design (specification) document would be needed.
Otherwise you could hire someone per hour, but is hard to know if they will not doodle around.
On way to get help reasonably quickly and cheap is using People Per Hour:
http://www.peopleperhour.com/drupal-hourlies/all?sort=relevant
If you have a design document you can just send it to one of them and get a quote
for example this one seems inexpensive / well rated
http://www.peopleperhour.com/hourlie/do-anything-in-drupal/18498?ref=search
If you want someone to do the management – draft the design document, manage change requests during implementation then you usually need a project manager.
I opened a company recently in UK on website development and we are already working with several clients, so would love to help with that for free.