I'm running Fedora 13 (Goddard) and when I was recursively removing a directory I noticed I had some files there I couldn't lose, so I interrupted the process with ctrl+c. Now I don't know if I lost any files. Do already deleted files came back to the original folder when I interrupt the process like that?
Already deleted files are not restored when you abort the process which is deleting files.
Now, if you were actually running
Depending on which file system you are using there may be undelete tools available, but if you are missing anything which you need, the easiest solution is probably to restore from backup. Since this isn't your system and you don't have root access, undeletes become even harder to perform; you'd need access to the raw physical device and you'd have to prevent any further disk writes to the partition(s) in question to minimize the risk that the data blocks get overwritten, and both of those are difficult without root access.
Some specialized file systems allow true transactional-style operations or have the ability to go back to a given past point in time (NILFS being one example) but those are practically unheard of except in specialty applications, which I doubt a 2-3 years old Fedora install will be.