SQL injection attacks problem

It seems my website is under attack from an SQL injection. 

How can I make it stop?

They are using a 'GET" statement fortunately and not a "DELETE" or "EDIT" statement. 

Is there a way to get rid of the injection or fool it to stop hitting the database?

Would duplicating the database and renaming the new one then changing all my connection codes work?

The delete the old database so they are not hitting the actual database.

I can't block the IP Address as they are using many of them.

Thanks

This might help SQL Injection Prevention - OWASP Cheat Sheet Series

The vulnerability is in your application code, not in the database name. Attackers exploiting a SQL injection flaw are not targeting a specific database by name; they are exploiting how your code constructs SQL queries from user input. I hope you are modifying your code as described in the article linked to previously.