Okies, let me suggest you read a bit about SEO (search engine optimization) before I go into details - here's a free ebook -
SEO - The Basics - I suggest you read it.
Then - looking at your site so far - I'm not sure exactly what you are focusing on - but I know it'll have to do with racing and that people looking for it won't be inputting the phrase dreams or budgets into se's to find you. So, that's a good phrase to have up in the header.
I hoped you were going to be adding text to the page - if not, you're in big trouble with the se's - as there is nothing there for them now. I thought the picture was the background and you just hadn't added any text yet. And, I do expect you to have a headline - but I want it to be with the right words.
An 800 width resolution is the lowest resolution being used now. I'd say 20-35% of users still have it. Personally, I make my pages at about the width you have - but very carefully, because people don't like to scroll left to right. If you don't want anyone to have to do that scrolling, you'll need to make the width no wider than 800.
That said, I keep close watch on my statistics and am seeing only about 10% of my users are at that width - and I have done the stores with a column outside the 800 - so they get the basic store and text without scrolling.
The decision is yours whether you want to chance that. As time passes, less and less will have that resolution - but will be several years before it totally becomes passe.