Visual Basic - Web Request 403 Forbidden - vb.net

Question

I am new to Visual Basic so I dont know much about Syntax e.t.c
So if anyone could help me out that be great!
Im getting a 403 Forbidden Error most likely because of the User Agent being used. The website is probably picking up that its not an actual user entering the Website and therefore blocks access.
How do I apply a User Agent that will bypass this issue? I have no idea where to put the Syntax.
My Code:
Imports System.Text.RegularExpressions
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim sources(1) As String
array(0) = "http://proxy-ip-list.com"
array(1) = "http://sslproxies24.blogspot.com/feeds/posts/default"
For Each element As String In sources
'Connect to the Proxy Source;
Dim source As Net.HttpWebRequest = Net.WebRequest.Create(element)
'Prepare the Response;
Dim response As Net.HttpWebResponse = source.GetResponse
'Load the HTML;
Dim reader As IO.StreamReader = New IO.StreamReader(response.GetResponseStream())
Dim html As String = reader.ReadToEnd
'Regex;
Dim expression As New Regex("[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}:[0-9]{1,4}")
'Set the Matches variable to the Matched Sections of the HTML source;
Dim matches As MatchCollection = expression.Matches(html)
'Add the proxies to the ListBox;
For Each proxy As Match In matches
ListBox1.Items.Add(proxy)
Next
Next
End Sub
End Class