I installed tortoise SVN on a 2008R2 server. The install completed, I rebooted, but still no tortoise context menus.
Did you perhaps install the 32-bit version of Tortoise?
32-bit shell extensions do not work on 64-bit Windows operating systems (Windows Server 2008 R2 is 64-bit only), which is why the context menus do not appear.
Download and install the 64-bit version and reboot the server.