Free extensions for Joomla!

Hi,

I am currently working on a directory project using Joomla. My client has provided with 50 million listings. I am using Joomla SOBI2 and community builder components to develop the website. I am finding it difficult to map the listings. As the database is huge, I constantly get 'session time out' error. Sometimes, the website crashes as well.

Can anybody help me with your suggestion of any other Joomla component to manage such database. What are my options, to stick with Joomla, yet map and manage the database.

In Anticipation...

Regards,
Kevin Kumar