I have a quick workaround for you until you make up your mind only if your website have a network of pages that are linked in someway and have appropriate descriptions and keywords. Create a SITEMAP page! The sitemap will be an html page and will have a tree-like structure leading to or from the various links in your website (pretty easy!). Add a link to this sitemap page to the footer of your current pages and now the search engine can find it`s way to crawl your site better....
You shouldn`t give up the idea of converting your current site to html. It can be converted to html and css and still utilize the exsiting design because there isn`t much animation going on there. We have done this before for one of our clients. The homepage of your website can then ask the user if he/she would like to enter the flash or html version of the website.
Also, this doesn;t mean that your investment in this flash website is lost! You can utilize the existing design by burning it to CDs and use it as a give-away portfolio of all your products/work that anyone can browse offline on his/her computer ... This is an excellent marketing tool...
For the price...I am not so sure about the total flash content of your site but if it is as simple as it looks it should definitly not cost $4200 and should be a fit for your current bugdet ($1200) or even less, especially if no new design will be created. I also noticed the site has a flash gallery. This will need to be replaced with an html gallery.
Hope that helps.