CRM email template design

We use a real estate CRM called Realvolve to send monthly email blasts to our contacts. We are looking to create a specific template for our monthly market update but are having trouble with the coding to mirror over from the design we are creating in Mail Chimp or Constant Contact. We have the design created but when the code is copied into Realvolve, the formatting is off (some of the colors do not transfer and sizing of elements in the design are not consistent). The rep for Realvolve explained that the system works with "inline style sheets". The objective of having this template is to be able to copy it every month and change out the photos for "just listed/ under contract/ just sold" and the details (address / purchase price / bed/bath) with everything else staying the same. We want to make sure the template is also mobile responsive. We can send an email showing what the template should look like and what it currently looks like once sent. We would like to have someone code the template so it sends properly.