Data accessing while database file size more than 4 GB

I am working on ORMLite-ServiceStack, ASP.NET/C# with a SQLite Database. I am facing the issue while accessing the data from Database file. The size of database file is 4.5 GB approximately.

I am trying to load the data by complex Sql query (atleast 6-7 million records in each table) by ASP.NET and using the SQLiteDataReader ExecuteReader(). The application hangs. In fact I am not able to run the SQL query via SQlite-Manager Firefox (Version 0.8.3.1) as well as GitHub SQLite browser. Both tool would become hang, I have to kill by task manager.

Please suggest any optimization tool or any configuration setting for SQLite database. So I can be able to access the data via web application or web service.