svn : import the directory with files forcefully even the directory is already exist.

Hi all,  I need to import the folder(say Project) with files to svn database even the folder already exist with the files.  Note : I have setup my repository as Write-through proxy, so if i checkout the folder, do the changes and commit back, It's showing "working copy out of date" error.  Is any command line tool to do this ? or any idea ?  Thanks in advance.