I was working with a single repository for a while. Now, I would like to create another repository for a different programming environment (that uses a different language and project altogether).
To do this in a structured way, I would prefer to have one root directory where I would be able to collect different repositories. But I can not find information on how to move a repository into a different folder with Tortoise. The "relocate" option seems only to work for items within an repository.
The definitive pointer for Subversion is the red book. All of the TortoiseSVN commands map to the commands described there.
It's likely that you can just move the repository on the filesystem and make the necessary server changes to keep the working copies' URLs up to date. In particular, see this section of the red book.
Relocate is exactly the way to go. Not for the actual relocation but afterwards to show Tortoise the new location.
First step: Create a new repository where you want it.
Second step: Dump your repository and load it into the new repository.
Third step: Relocate (that's just a rewriting of the urls).
As Michael said, your best bet is to read the svn book, I'd also recommend the TortoiseSVN manual for information on server setup on Windows.
Some comments though:
You don't need a different repository if you structure your single repository in the appropriate manner. An example is the apache svn repository. Having a single repository makes for easier maintenance, but if you want your revision numbers sequential for each project, then the only way is separate repositories (not a common requirement).
If you decide that separate repositories are the way to go, and are using svnserve, then make use of the --root or -r option. It also sounds like you want to create a new repository, rather than relocating an existing repository, so a dump/load probably isn't the appropriate action.
You can move repositories around on the same server, without worrying about interfering with client working copies (after stopping the svn server of course!), but this assumes your svn server is configured correctly i.e. knows about the change. This has nothing to do with TortoiseSVN. TortoiseSVN is an svn client, the only server operation TortoiseSVN performs is repository creation (for convenience).