How to increase the top-margin of loop in showcase theme?

I am trying to use bigger logo on the site. (151×151 size atm, which will be changed to a banner.)

I have put menu on Left float and have put it before the logo because i have lot of pages to place in the menu area, and right float is taking whole menu below the logo. (in original showcase theme, logo is present before the menu and logo is left float and menu is right float.)

I have increased the TOP-MARGIN of LOGO and Flash Content. But flash content (3D SLIDER) is overlapping the LOOP / the BOX (the three posts with image on top).

Kindly advice me, how i can push the loop a bit below without disturbing the footer area. (increasing the overall space between the 3D slider and Footer, so that loop can be adjusted without getting overlapped by slider.)