Take a basic email and dynamically populate HTML template email

We have a quote system that generates a basic email - it does not have an API. We need the info generated that gets delivered as a basic email to be put into a template and emailed to an end user.

Attached is a screen grab of the basic email and a screen grab of the HTML email template.
We can provide the HTML for the email. I think we would need something like Zapier in the middle to handle this, but we want it to be a fully automated procedure so that the end user only sees the populated HTML template email.