modal popup related

Question

hi there

<marquee scrollamount="5" width="100"><span style="color:Red"><<< </span></marquee><a href="#" id="A2" runat="server" style="color:Blue; font-weight:bold" >PROJECT COST MONITORING SYSTEM </a> <marquee scrollamount="5" direction="right" width="100"><span style="color:Red">>>></span></marquee>
<asp:ModalPopupExtender ID="ModalPopupExtender4" runat="server" PopupControlID="Panelcostmonitoring" TargetControlID="A2" CancelControlID="Button3" BackgroundCssClass="modalBackground" >
</asp:ModalPopupExtender>
<asp:Panel ID="Panelcostmonitoring" runat="server" CssClass="modalPopup" align="center" style = "display:none">
<div class="header">
</div>
<div class="body">
<iframe style="width:700px; height:500px; border:none;" id="Iframe3" src="CostMonitoring.aspx" runat="server" ></iframe>
<br/>
<asp:Button ID="Button3" runat="server" Text="Close" CssClass="Button" Height="34px" Width="123px"/>
</div>
</asp:Panel>

i had coded a link where pressed a modal popups for login and when my login is successful it redirects in that modal only and not in different web page i want that if logins is success the it should redirect to different web page and not just on the modal popup