I had to update Windows 2008 R2 to Service Pack 1 as the first step. Windows 7 must be on SP1 as well.
Microsoft KB 3080079 adds support for TLS 1.1 and 1.2 for Windows 7 SP1 and Windows 2008 R2 SP1 but DOES NOT force use of it (see later steps):
Apply KB3140245 to Windows 2008 R2 SP1 server and to Windows 7 SP1. This KB gives the ability to set TLS 1.2 as the default protocol. The article also explains how to set it as default on both Win 7 and Win 2008 R2:
Enable TLS 1.2 on Windows Server 2008 R2 SP1 and Win 7 SP1 after the above KBs are installed. The article applies to Windows 7 SP1 also, though it doesn’t state that:
Windows 7 and Win2008R2 TLS/SSL settings reference. More info than you need to simply enable TLS 1.2, but might be useful: