With nearly 20 years Classic ASP experience I can debug, rewrite, improve performance and security of your ASP site including database integration, json, xml, javascript and server configuration issues.
I am especially experienced integrating with 3rd party API's using SOAP/oAUTH2 etc, as well as developing secure API services in ASP to support customer and application access.
Experience of the most popular plug-ins also e.g. Persits applications for upload, PDF, emailing etc
That said, looking at your site, I'd be inclined to redesign using a framework such as Bootstrap for the visual layout (since mobile friendly will also win you points with Google) and replace the ASP code with ASP Razor, MS's new answer to Classic ASP; Codes in either C# or VB but is simply scripted like Classic ASP. You site doesn't appear to make many scripting demands on face value so this might be the way to go. I would need to know what, if any 3rd party COM components you use first to be sure.
I look forward to being of service