Masterpages and CSS

I am trying to use my CSS file with master page but its not working. I have my css file in Theme folder.

<%@ Master Language="VB"%>
<%@ Register Src="~/menuWinXPThemes.ascx" TagName="menuWinXPThemes" TagPrefix="uc2" %>
<%@ Register Src="~/menuMSNThemes.ascx" TagName="menuMSNThemes" TagPrefix="uc1" %>


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<script runat="server">
Private Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)

'Me.WebPartManager1.DisplayMode = WebPartManager.BrowseDisplayMode
Dim link As New HtmlLink
link.Href = "C:\Users\c-bkatoch\Documents\Visual Studio 2008\Projects\LocalShareReports\LocalShareReports\App_Themes\MySite\MySite.css "
link.Attributes.Add(Htm ...