banner problem

Hello there i have asked this question before but nobody helped i dunno why anyway
my prob is that i m running a blog its a simple blog on weblog.com
there i have 2 banners when a visitor clicks on banner the whole blog redirects to the website ( the one whoz banner was clicked )
i want to open this banner in a page page whenever visitor clicks on them
banners are already there just let me know what exactly should i edit to make them open in a new page

please please help