organizing web parts on asp.net form

I have form and i'm using web parts for asp.net.
 
I want the first web part the stretch the entire width and on the second row I have 2 small web parts to on the second row
<big web part>
<second><third>
 
But, I can't get the 2nd and third web parts to be on the same line. Can someone tell me what i'm doing wrong?
<div style="display:block; width:1000px; height:1000px;"> <asp:HiddenField ID="hidEmployeeId" Value="72" runat="server" /> <asp:WebPartManager ID="WebPartManager1" runat="server"> </asp:WebPartManager> <asp:WebPartZone ID="WebPartZone1" runat="server" Width="900px" Height="300px"> <ZoneTemplate> <uc1:DCSEventWebPartUserControl ID="D ...