HTML Form posted from Email

I have a client who needs to be able to get back responses to an email and process them automatically. We have a tool that will query our database and send out an HTML email. Embedded in the email is a form. The user needs to make one selection by pressing a radio button and then pressing a submit button. My clients web hosting provider only processes cgi and php requests for forms submitted from within the domain, not from an email. I need to find someone who can help develop a cgi or php form handler that can accept a post from anywhere and then send the result back to a fixed email address. Once I receive the email back, I already have a tool to parse it and put the contents into a database for my event handler to act upon. Please let me know if an HTML form and handler can be created such that the form would be emailed and then posted from an email client. If this can be done, please respond with an estimate of the cost and timeframe. Thank you.