Secondary SQL Server DB one-way syncronization

Hello, 

I have installed SQL Server 2008 R2 Express.

I need to create a secondary SQL Server DB from the production one with this feautures: 

The secondary DB has to be a specular copy of the production one the secondary DB it's populated with a real time one way syncronization (from the production DB to the secondary)

 I need to be able to add tables or data on the secondary DB without change the primary How can I obtain this type of setup?

The synchronization must not cancel the modifications made on the secondary.

Thank you in advance