Custom database search…

Ok so here goes my lengthy explanation… (I figure if you have the whole picture I am more likely to receive help that matters!)

I have a database that contains near 1.3 million records in each of 3 different tables. This database contains information for every “Amateur Radio Operator” (Ham Radio) in the US and its possessions. I have back end shell scripts that do a daily update by downloading raw pipe delimited data from the FCC and loading it into a database. On Sundays it wipes the database and reloads it with the latest complete database available from the FCC.

Then I have a page where someone can go to search for themselves or others. Do more advanced searches based on partial callsigns or location based searches etc. With more planned for the lookups in the future.

Here is a sample page:
http://chadsystems.us/csdb/

I want to incorporate the lookup and responses into a WordPress page. The database exists outside the WordPress database structure. So my problem becomes these…

a) How do I incorporate the lookup page into WordPress
b) Once there I cant just pass a search term to the page I have to pass it WordPress who in turn needs to pass it to my page.
c) Once there the script needs to display itself inside that same page.

I HATE IFRAMES, LOL So that is out there I know I can incorporate the scripts into an iframe tag but that is just hinky and I want a smoother way of doing this that is integrated into my WP installation.