Analysis and technical specification to build web service

I need someone who can develop comprehensive technical requirements to build a web service based on a similar functioning website and some basic business requirements. In addition to the technical requirements specification I am interested in your assessment of the estimated cost to time needed to develop the e-commerce application. We have a very small budget and want to get a feel for the level of effort and cost to build a website that we can continue to invest in so we can provide low cost legal assistance for basic legal documentation tasks. The analysis from this job will become the foundation to post on freelancer for development. The best way I know to post this job on freelancer is to ask bidders to review another website to get a feel for the scope of our initial project so you can define the best technology to build this solution, what it will cost to build it, and how long it should take. See attachment for more details.