How to get latest file based on date in file name

Hi,
The is my filename
File_20131204 File_20131211 File_20131212 File_20131213
Here I want to get the file "File_20131213" alone. The below is the code which I have used to get file from directory.
Dim sFilenames() As String = {}
sFilenames = Directory.GetFiles(AppSettings.Item("FilePath")). All the file found in directory will in the sFilenames array variable.
Please  post solution for this post.
Thanks in Advance