I have been living here on a marriage extension for about 2 years. This year I have to go back to the states after my 3rd 90 day check in. I won't be coming back until 3 weeks after the end of this years extension. I assume I will have to refile for a visa while back in the states But I was told that if I get an exit permit that I would have one week after my return to get an extension on my original. I have never hear of this before and find it hard to believe it to be true since I would be returning on an expired extension.

Nope, never heard that one. I think you'll have to re-start the process from scratch

Crossy is right, you have to buy a new VISA in the states.. And also note what you are talking about is called a Re Entry Permit...

Meaning we are talking about Re Entry..... NOT Exit..

Glegolo

As said, you will have to get a new visa in the states.

The 7 days that person talked to you bout was a mistake. That is for doing a 90 day report. For an extension you must apply before, or the day itself at the latest, your permission to stay ends. You can apply for an extension 45 days early.