Widget advertising code gives wrong size and colour

Hello, I'm using the Helena pro theme for a while now on http://www.diydiva.nl/, and I like it a lot. I have a question. I use Google Adsense on my blog in the footer and in every blogpost in the sidebar. In the widget advertising code it has a too big red frame behind it. I want to remove this frame (or make it colourless...). I also think my adds are made smaller by the Helena theme. Can you please fix those two problems? Thanx, Martine