ADD to a txt file? [RESOLVED]

[Synth3t1c]

I know how to write a text file and i am using the following code:

Dim Name As String = Textbox1.text
    Dim strPath As String = "C:\bdtwinners.txt"
    Dim SW As StreamWriter
    Dim FS As FileStream
    FS = New FileStream(strPath, FileMode.Open) 
    SW = New StreamWriter(FS)
    SW.WriteLine(Name)
    SW.Close()
    FS.Close()

How would i add on the file? this clears the txt file, or at least the 1st line