CSS - Urgent help needed

Positioning an element absolutely removes it from the flow of the document. That is, other elements will essentially not know (or care) that the absolutely-positioned element is there. This is part of the reason for your problem.

As you are using tables for layout (I do not condone it, but that is not relevant), why not put the heading stuff in a TD which spans all columns of the table?

Jam it back in, in the dark.

There's no really "quick" way to replace them. You can use absolutely positioned/sized container elements (such as a DIV) to structure the site, but this is advised against by most for concerns of accessibility/usability or semantics. What I reccomend doing is using floats--with containers or otherwise, they are quite easy to work with and the code for them is small, and easy to manage.

For examples, the first is an example of my work. The second is the site of a person I speak with on this very issue:

Site: http://www.spur-me-on.com
CSS: http://www.spur-me-on.com/style.css

Site: http://www.arctic.kyoushu.com/
CSS: http://www.arctic.kyoushu.com/main.css

There's nowhere I can't reach.