Interfearing with the design / article loop

[ Moderator note: moved to Fixing WordPress. Please do not use Developing With WordPress for these topics. ]

Hi there,
i was wondering if someone could help out with something. In the attached picture, you can see the layout of the wordpress default theme/installation

By default, it uses the articles/posts column and the right sidebar (if you have configured it that way).
I managed to write a function, where every x posts an new row appears, and it inserts something different, like a video. That works great.
Now when the widget column has a lot of widgets to show, its content overlaps with the full width video row.

and the big question is, is there a way, to figure out, when the widget on the green column will overlap with the full-width video row, so it will not display its content over this row, but instead to continue after the full-width video row normally.

any help/direction would help.

thank you in advance

Jan