Creating Space Between Windows or Fields On Page

I’ve added small bits of code for banners and URLs of directories etc. Recently a new ad 125×125 px was installed but didn’t end up where I wanted it. It actually appeared to be contiguous with a previously installed window of ads, only it is outside of the field and not centered beneath the ads above it. I want to create a separating space of about 1/8+ inch and center it under the ads in the field above it.

My blog is: https://www.bloggasaurus.com and the problem Ad is Seedbuzz.
what is the correct code to add that will separate this ad from the field it is touching above it?

Thank you in advance for your insights,

Wil