Can I just move them to time capsule to solve the problem? If yes... how do I do that?
Are you using the TC for TM now?
If yes, then to store data you are better creating a disk image.. although it is not absolutely essential.
Look at Q3 here. http://pondini.org/TM/Time_Capsule.html
To move data onto the TC.. copy it and paste it.. via finder.. it is nothing more than that.. delete it in the Mac once you have copied it. (and then empty trash). There is no move as such except to trash.
But if you intend to move itunes library or iphoto or any other library there is specific info..
eg moving itunes.
http://support.apple.com/kb/HT4527
And there is a huge caveat..
The TC has no way to back itself up.. and TM cannot backup a network drive.
So your files are now moved to a single location.. without backup and without even a method to back them up.. and you can guarantee at some point you will corrupt a library or wipe a file or the whole TC drive de-format itself. What will you do then??
The TC is never was never and never will be a NAS.. it is a back up location for TM. Use at own risk.