Tk is fine for an X connection over, say, ssh, but is not suitable for http. It would be absurd to convert screenshots of Tk into imagemaps.

The GUI will need to be translated into HTML forms and perhaps some Javascript. The serverside will need a cgi layer which calls your present program logic. That should be doable if your code is well factored.

You're not forthcoming about what your buttons do or what your application accomplishes, so it's difficult to give more detailed advice.

After Compline,
Zaxo