I have had many clients come to me with older frame build sites, which we have unframed, and they've been way better for it in the SERPs and for many other reasons too.
Here's your original site index page...
<frameset framespacing=0 border=0 rows=89,71* frameborder=0>
<frame name=banner scrolling=no noresize target=contents src=mainlogo.htm marginwidth=0 marginheight=0>
<frame name=_toc target=main src=maintoc.htm scrolling=no marginwidth=0 marginheight=0 noresize>
<frame name=main src=home.htm scrolling=auto noresize marginwidth=0 marginheight=0 target=_self>
Now if you are on a linux server you can use a .htaccess file to allow the server to parse server side includes for .htm (or whatever extensions your site is now)...
Then do this...
<!--#include virtual="/mainlogo.htm" -->
<!--#include virtual="/maintoc.htm" -->
<p>content from home.htm goes here OR include the home.htm page (only for index rest of pages actually copy paste the content into this area then name the new page what the old frame was called.</p>
do that for each page .. done your site doesn't rely on frames anymore...
Once you're frameless you're off to the races anytime you want you can redesign very easily.
You can change the names of the files for the header / nav also..