Need Production App (complexity equal to full facebook production site plus three app modules)

We have a demo site that we can describe in detail after you sign an NDA. We have a meeting with investors next week and following securing funding we will launch development to complete the site and turn a hastily coded, copied-and-pasted from various open source programs site into a polished, production ready web app. The complexity of such a program and number of pages is comparable to facebook. Price this based on most is completed, but should not be considered a solidly programmed production app. The look is very rough, and is programmed the old way using tables. It is our desire to bring this site to the most modern possible web 2.0 specs. There will be various modules in this site. It may be necessary to rewrite some of the code. If there is any reason why Joomla should not be the base of this program, then price a complete rewrite. Deadline is a firm 2 months, including all testing. Following completion we will have penetration testing, and you must fix all security problems as well.