How do I upload a new version of my project to SVN (eclipse)?

I have a Java project in an SVN server. I created a whole new version of it and now I want to "commit" but keep the previous version on the server. I'm not allowed to use branches on this project. So I've changed the new project's name to projectName_improved. I created a new folder for the project on the server. Now I want to upload projectName_improved to the new folder. I'm using eclipse (+SVN plugin). How do I technically do it (without branching)?

EDIT: The plugin I'm using is Subclipse.