#select files older than 2 hours
$date = Get-Date
$start_date = $date.AddHours(-2) 

#cleanup destination directory
Remove-Item MY_DESITNATION_DIR* -Recurse

#copy
Get-ChildItem -Path Backup -File |
    Where-Object { $_.LastWriteTime -gt  $start_date } |
    ForEach-Object {
        Copy-Item -Path MY_SOURCE_DIR$_ -Destination 'MY_DESITNATION_DIR' 
    }