Can I change the Style attributes?

Is there any way to change the styling? Meaning can I change what the sizes are for Title, or eliminate the code and such things that are in the Styles drop down menu?

What I need specifically is to not allow any <h1> or <h2> headings, because in my website's CSS I have these controlling my website heading that is positioned absolutely. When someone inserts an <h1> or <h2> into the editor and submits it, when pulled from the database it joins my heading.