When I started programming web pages in 1998 we used to build 2 sites, one for explorer one for netscape. I small script would ask the browser which version was needed and send it to the relevant page. Very easily done.
The very least your "web designer" has to do is test in the most common browsers (about 7!) and make sure everybody can see the content. Up to 70% of people (depending on target group) use firefox. That's a lot of clients you are losing !
If your "web designer" doesn't like html he could at the very least make a front page and tell firefox users to get the IE add on IE tab (
http://addons.mozilla.org/en-US/firefox/addon/1419).
Not that many people will though, like others said before, people go elsewhere if things are too complicated. I certainly do and 10 years of web design experience tell me the same.
But I don't understand the theory behind it as only the front page is flash.
I managed to open your page in Safari, but the loading page is a big no no. 47 seconds to load! Nobody will wait that long for a page unless something is telling them what is happening or part of the page is loading during the wait.
Another thing I don't understand is why all the pages are made in html code and pop up in a new window, I had 9 open within 2 minutes. The pages also don't fit on my screen, so I had to scroll sideways.
Please see all this as a way of trying to help, I don't want to attack you, but all in all the design is very unprofessional and also the text is as well.
To find a good web designer you don't need to look local, there are thousands available online with respectable portfolios. You have some good content there, you just need to present it better.
Make sure you don't pay upfront, but in stages, keeps everybody happy. That's what I used to do with my clients.
Hope this helps a bit in getting things sorted.
Stefan