Web design and Programming - scripts intergration

I have the following scripts which i want to merge to create one website;
email script
Social networking script
shopping cart script
search engine with adserver

What i want is for these scipts to be merged so that they have a common log in that ensures seamless transition from one script to the next without any hicups or delay. the adserver should be merged so that all the scripts adservers are linked to and can be controlled from the search adserver as one. i have not found out what the languages for these are but will find out and communicate. there will hardly be any design work as the providers are already modifying their scripts. the only requirement is intergration.

Quote required please.