Create a detailed wifreframe, prototype or mockup design for a website

We are a new dental recruitment agency that specializes in recruiting and placing temporary dental nurses on short notice. We are after a detailed mockup, wireframe or prototype design for our website. We then plan to use this wireframe, prototype or mockup to further outsource the coding and graphics. The website will be aimed at 2 distinct and separate user groups; Dental nurses looking for temporary work, and Dental practices looking for temporary nurses. I would like the site to allow nurses to create an account, insert there details, work preferences, bank details etc… I would like the nurses to be able to log in and to be able to change some of there details if they wish. I would like Dental practices to be able to use the site to request dental nurses. This would then create a log or an email that would then allow us to fulfill the request with an appropriate nurse. I need to be able to search the data base of nurses. I would also like to add ‘hidden’ data to the nurses profiles such as feedback from dental practices. I would also like to be able see a log of the requests dental practices have made. It would be nice if I could do these things through a backend of some sort. However if we can create a cheaper solution that allows these functions to be fulfilled without a backend I’d be interested to know about this option too. Initially I would like any backend to be quite simple to keep costs down. But I would like it to be built with future capabilities in mind. Such as being able to summaries nurses jobs, and pay summaries, and even post there payslips into their user accounts. At this stage I am after someone who can work with me to create a detailed web design only, but not to necessarily code it. I know what I want the website to do, but I’m having trouble documenting it and deciding on the user flow and site structure. So at this point I would to just like to get a detailed wireframe or prototype made up, so I can get a detailed web design documented. I’m happy to have you guys code it and do the graphics too. But I would only want to discuss this after the detailed wireframe/prototype is well designed and documented.