Well, I don't have the precise solution for each of your issues but I do notice something in your CSS file and in the way you are structuring your HTML.

*CSS:*
Try to avoid the use of position:absolute; unless, lol, is absolutely necessary. Doing this may prevent space issues like the ones you are experiencing. In my methodology I barely use position:absolute;

*HTML:*
You are using so many DIVs (honestly, an overkill of DIVs) that not only some of them are totally unnecessary but you are defeating the purpose of HTML tags.

For example:

The introduction area of your website, where the "__Welcome to GP insider.__" title is (BTW, Titles and Subtitles do not use a period).

This is your current code:
************
<div id="frontbox2">
<p class="fontstyle2">Welcome to GP insider.</p>
<p class="fontstyle4">A website for Australian Doctors working in General Practice.</p>
<p class="fontstyle3">GP insider has been designed to facilitate discussions relating to current research, medications, treatments, clinical practice guidelines, health policy, and the future of the profession.
Signup now to start submitting questions to the community for discussion immediately.</p>
...
</div>

************

This can be cleanly done like this:
/////////////
<div id="frontbox2">
<h1>Welcome to GP insider</h1>
<h2>A website for Australian Doctors working in General Practice</h2>
<p>GP insider has been designed to facilitate discussions relating to current research, medications, treatments, clinical practice guidelines, health policy, and the future of the profession.
Signup now to start submitting questions to the community for discussion immediately.</p>
...
</div>
/////////////

And the CSS would be:

////////////
p {...}/*Probably all your paragraphs would look the same to maintain consistency across the site.*/

#frontbox2 h1 {...} /*Heading 1 inside #frontbox2 -- "Welcome to GP insider"*/

#frontbox2 h2 {...} /*Heading 2 inside #frontbox2 -- "A website for Australian Doctors working in General Practice"*/
////////////

--

You seem very proficient with HTML and CSS, I don't think there's much I can teach you, but if you take into consideration what I said here maybe some of your other issues might get automatically resolved.

Bytes,