How to re-size Banner and a few questions

[selectworldtravel]

Well after quite a few weeks of having my site down, Thanks to Brian it is up and running. Brian has loaded the Demo version of the Lifestyle Theme so that We can work backwards in effect. To Us Newbies it has helped to see how the Layout should Work and I can just Highlight Brians Content and start to take this out and replace with our own posts etc.
Our site is at www.selectworldtravelblog.co.uk

First Question.
I have managed to take out the Code for the Ad Banner on the Header and have managed to Upload our logo Banner. This should be 940pixels by 100 pixels. We Have used Picassa 3 to upload this, but when Picassa gives the embed code, the maximum it goes up to is 800 Pixels. I have tried in the coding to change the 800, but this obviosly is not liked by the Picassa coding. Here is the code from picassa and currently in Header php.
<div id="header">
<div class="headercenter">
<table style="width:auto;"><tr><td></td></tr><tr><td style="font-family:arial,sans-serif; font-size:11px; text-align:right"> </a></td></tr></table>
</div>

Is There a better uploader I could use, that would allow us to keep the original size of the banner? Or a hepful explanation of how to upload properly?

Question Two.
The Newsfeed and Comments boxes at the top, seem to be Misconfigured , How can these be restored to be properly used?

Question Three
The Featured Video box seems to be missing , How can this be restored as we want to use it as an integral part of the Site?

Question 4.
The Right Hand navigation Bar seems to have slipped below the Left hand Cotents boxes, How can I restore this so the page is neat and tidy.?

Any other Hints and suggestions greatly received