Hi Gina,
I had the same issue with a couple of properties we acquired. However, rather than start from scratch, I found the buildings' plans in storage and used those to create new brochures, etc. When I wanted to remodel, too, I was able to use those building plans/renderings. I have found every property has them (or at least a copy on site) but like me, you may have to dig through every storage closet and even the attic/basement to find them. The renderings are impportant to have because it illustrates shut offs, size of roofs, all the mechanicals and the original landscape plan (since some cities require you keep landscaping axactly as originally designed and require a variance to change things.) Once you have them, you can use a service that creates 3-D plans for website, etc.