Are you looking for a replacement for TMG now that its end is nearing. You could buy a thirdparty reverseproxy from Sophos og some appliance. The simplest solution is probably to install a Windows server 2012(R2) and add ARR module to IIS.
To install this module you would use the
Microsoft Web Platform Installer
All information you will need are at the IIS web site : http://www.iis.net/downloads/microsoft/application-request-Routing