hwo to move nested folder as it is to sharepoint document lib

Hi All,
     I putting up a script together to move nested folders with files in it to a doc lib n sharepoint as it is
I'm sure i should be able to use powershell for this and i need an assistance ... almost there.

This snipped does work but i get error:

Method invocation failed because [System.IO.DirectoryInfo] doesn't contain a method named 'OpenRead'.

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

#[System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint") > $null

[System.reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint") 
[System.Reflection.Assembly]::LoadWithPartialName("System.web")

function UploadAllFiles($WebURL, $DocLibName, $FolderPath)
{

 #Get the Web & Lists to upload the file
 $site = New-Object Microsoft.SharePoint.SPSite($WebURL)
 $web= $site.OpenWeb()


#Get the Target Document Library to upload
$List = $Web.GetFolder($DocLibName)

#Get the Files from Local Folder
$Files = Get-ChildItem $FolderPath 
#You can filter files by: -filter “*.pdf” 

#upload the files
foreach ($File in $Files)
{
    #Get the Contents of the file to FileStream 

    #Error here Method invocation failed because [System.IO.DirectoryInfo] doesn't contain a method named 'OpenRead'.
    $stream = (Get-Item $file.FullName).OpenRead() 
	                      
    $uploaded = $List.Files.Add($File.Name,$stream)               
    
	$stream.Dispose()
}

#Dispose the site object
$site.Dispose()
}


#call the upload function
UploadAllFiles "http://ServerName/" "TestDoc" "D:\myrootfolder"

This works but it doesn't copy the nested folder across as it is it just copies only the files inside the root folder.

Any help will be appreciated.

Thanks a lot