Getting Links off of page error

[VisualBasic2008]

I am creating a program and have the following code to extract the URL's off of a webpage and put them in a richlistbox. This is only from one page. The problem is that I am only getting one URL into the listbox, instead of all of them off of the page.

Here is what I have so far:

Private Sub Timer3_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer3.Tick
        Dim str1 As String = WebBrowser1.DocumentText
        RichTextBox1.Text = str1
        Dim web As String = str1
        Dim radar As String = web.Remove(0, web.IndexOf("/members/earn/offers/go/")).Remove(0, 1)
        radar = radar.Remove(radar.IndexOf("target"))
        RichTextBox1.Text = radar
        Timer3.Stop()
    End Sub

Any help would be great