Embedding an AppEngine App In My Website - Impossible?

First I should mention that I am NOT a developer.

I did hire a developer recently though, and he built me an app on Google AppEngine. I want to embed that app into my Wordpress website. I assumed it would be as easy as embedding a YouTube video, but it's looking to me like embedding the app might actually be impossible

Is there any way to accomplish what I'm trying to do? I want the app to appear inside of my WordPress site - you know, surrounded by my header image at the top, menu down the side, etc... I want it to appear just like any other page of my website. Also, I want to remove my app from myappname.appspot.com - I don't want anyone to be able to access it there.

I did read this - developers.google.com/appengine/docs/domain - and I started following those steps until it seemed like I was required to have the app appear on a subdomain of my website (i.e. myapp.mydomain.com) rather than just a regular page of my website (i.e. mydomain.com/myapp), and it started talking about domain mapping and CNAME (what is that all about??).

So, is there a way to do what I want, or am I screwed because my app was developed on AppEngine, and I need to hire someone to rebuild it from scratch using some other method?

Thanks in advance for any answers!

Please forgive me if I've posted this in the wrong section - if I did feel free to move it to the right place...

It might be possible to embed using an iframe. Is there anything about the page on the current site that you want to change or remove, or do you just want your header and footer surrounding what's currently there?