There may be little seo benefits between a well constructed table site and a well constructed css site except that the css version is likely to have less code and more relevant information presented in a more structured way which should aid seo. If the table site is well constructed then there would be little benefit in changing it solely for seo but more importantly tables should really only be used for tabular data these days.
Your site has no structure and no headings which are one of the main things that search engines look for. You don't even have an h1 which is the most important element on the page. Get some structure in the page, use proper headings and semantic html elements and the rest will follow. Don't design with seo in mind but more with users in mind.
Of course, I care little about seo as its users that I care about and they should come first.