How to extend the timeout of a SQL query

If you are using the EnterpriseLibrary (and it looks like you are) try this:

 Microsoft.Practices.EnterpriseLibrary.Data.Database db = Microsoft.Practices.EnterpriseLibrary.Data.DatabaseFactory.CreateDatabase("ConnectionString");
 System.Data.Common.DbCommand cmd = db.GetStoredProcCommand("StoredProcedureName");
 cmd.CommandTimeout = 600;
 db.AddInParameter(cmd, "ParameterName", DbType.String, "Value");

 // Added to handle paramValues array conversion
 foreach (System.Data.SqlClient.SqlParameter param in parameterValues) 
 {
     db.AddInParameter(cmd, param.ParameterName, param.SqlDbType, param.Value);
 }

 return cmd.ExecuteScalar();

Edited to handle the paramValues array directly based on the comments. I also included your ConnectionString value:

Microsoft.Practices.EnterpriseLibrary.Data.Database db = Microsoft.Practices.EnterpriseLibrary.Data.DatabaseFactory.CreateDatabase(connectionManager.SqlConnection.ConnectionString);
System.Data.Common.DbCommand cmd = db.GetStoredProcCommand("StoredProcedureName", parameterValues);
cmd.CommandTimeout = 600;
return cmd.ExecuteScalar();