Hi Kimberly,
You are in a highly optimised business so without a decent budget, money on Search Engine Optimization may be wasted anyway. Are you sure that more "random" search traffic would turn into more customers for you? Getting search traffic is the start, using your site to convert customers is a whole other matter and all this may not be money well spent.
Some studies have shown that, in crude terms, only 10% of searches are transactional (10% navigational and 80% informational).
Toon is correct that your site could benefit from a little more accessiblility but, other than some more search orientated content, any
SEO fiddling around is not worth the time. You'd be better off installing Wordpress, All In One
SEO pack and blogging your way to more customers.
If you are convinced that searchers are the way to get more work from your site, build a sales page and run an Adwords campaign that is targeted to turn keywords into real customers. If it doesn't work you can pull the campaign without spending all your budget.
I don't like to talk myself out of an
SEO job, but don't forget the "old" off-line ways of getting people to your site are still valid.
Rob