SQL Server 2008R2 - how to install replication components

I am trying to install the Replication components for SQL Server 2008R2, on technet website it says:

1. On the computer that is running IIS, insert the SQL Server 2008 R2, SQL Server 2008, or SQL Server 2005 CD and run Setup.exe.

2. In the SQL Server Installation Wizard, on the Components to Install page, click Advanced.

3. On the Feature Selection page, click Client Components, and then click Connectivity Components to install the SQL Server replication components

But the CD is lost, is there anyway to download the components or the setup files online?

Select @@version

Microsoft SQL Server 2008 R2 (RTM) - 10.50.1600.1 (X64) Apr 2 2010 15:48:46   
Copyright (c) Microsoft Corporation  
Developer Edition (64-bit) on Windows NT 6.1 <X64> (Build 7601: Service Pack 1)