Big Help needed... Need to integrate two web products

[veer]

Hi guys,
I have created a webisite as an internal product of our company where users login and do some stuff. It was done using XAMPP stack with Joomla CMS. It was hosted using window server2003. Its running fine.
We have another webproduct done using (Ruby on Rails ) which is running on linuxserver. Now the task is to integrate these two webproducts so that they run synchronously.

Issues:
1. The two products are running in different servers ( windows server2003 and linux )
2. Both these products have different database tables and different authentication mechanisms.

Taks:
1.Have to integrate these two products and make them resemble as a single product.
2.Integration of database tables.
eg: The work flow is from first web application to the second web application. Suppose if the user is logged in the first webapplication and clicks on the link to the second webapplication, the user has to be automatically logged in the second webapplication.
and when ever a user is registered in the first webapplication , it should reflect in the second web application.
ie., The authentication process (especially user database) needs to be synchronized between the two web application.


A BIG HELP NEEDED TO SOLVE THIS ISSUE.. Time is very less... pl do reply..

Thank you...