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
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.