How to add text/ad AFTER More/Excerpt in posts

Hi

I want to add some text or an ad after the ‘more’ tag or after a custom excerpt i.e.

– More text first

– image/custom text or ad

– then rest of post

Loopinsight.com has managed this on their posts e.g.

http://www.loopinsight.com/2011/02/25/verizon-ceo-says-iphone-sales-strong/

An ad is displayed after the more/excerpt:

Verizon Wireless CEO Daniel S. Mead told The Wall Street Journal that sales of the iPhone 4 were very strong, contrary to reports that the phone wasn’t selling as well as expected. The article, penned by Shayndi Raice, included some other tasty tidbits too (it’s behind a paywall).”

an ad, and then the rest of the post.

Thanks in advance for any help