The TortoiseSVN installer comes as an MSI file, which means you should have no problems adding that MSI file to the group policies of your domain controller.
A good walk-through on how to do that can be found in the knowledge base article 314934 from Microsoft: http://support.microsoft.com/?kbid=314934.
Versions 1.3.0 and later of TortoiseSVN must be installed under Computer Configuration and not under User Configuration. This is because those versions need the new CRT and MFC DLLs, which can only be deployed per computer and not per user. If you really must install TortoiseSVN on a per user basis, then you must first install the MFC and CRT package version 8 from Microsoft on each computer you want to install TortoiseSVN as per user.