Why you have not mentioned your current technologies? I think this is very basic and if you was clear me about it may I would be able to give you a proper suggestion in this proposal. As I am not aware at all about the current one so it is important for me to check once what is there. So, when you will ping me please share me your current site so that I can investigate on it and can give you an exact architecture.
Regarding content, users and current data do not worry. If at worst case I need to create the site from scratch in that case as well I will save all the records from your current site and migrate to your new site. May I will have to write a small script but it's easily possible.
Now, FYI, there is module called Drupal Feed module. This module help us to import content, views and data into Drupal site. So, what CMS you are using now, we need to export the data in Drupal Feed XML format. So, until I will not check the current structure of data it is bit difficult to commit you anything.
Benefits:
- Payment plans are broken down to milestones, and include penalty clauses for late delivery.
- An one month warranty is given with all projects
- All correspondences will be replied to within 24 hours
- I will send you screenshots and samples that how it will look
I want to jump on it and want to check everything to start work on it. Please let me know if you are free today.