A group working to renovate and reopen the Denis Theatre in Mt. Lebanon signed a sales agreement Wednesday to buy the building.

The Denis Theatre Foundation agreed to pay $668,750 for the theater on Washington Road. The theater, which opened 72 years ago, closed in 2004.

The deal should be final within 60 days, said Anne Kemerer, the foundation’s executive director.

“This is almost like an unattainable dream, especially after the economy got bad and fundraising became so difficult,” Kemerer said. “To me, a main street has a theater on it.”

The foundation has raised $663,000 and aims to raise another $1.8 million for the first phase of the renovation, which includes opening one screen, updating or replacing basic systems and installing an elevator.

The Encore, the first of three planned screening rooms, is expected to open in 2012.

The project’s second phase includes opening two more screens, restoring a stage in one theater and adding meeting rooms.

So far, the foundation has received 436 donations — the two largest are $155,000 from an anonymous benefactor and $100,000 from The Pittsburgh Foundation.

“The goal of this project is to serve a wide demographic over the South Hills. There is something about a community theater that makes a community stronger,” said Mark Lynch, a spokesman for the foundation.

The Denis opened in 1938.

“I remember standing in line to see ‘Benji’ there. The Denis Theatre is an historic building that holds lots of nostalgia for people in the area,” said Jennifer Smokelin, a foundation board member and Mt. Lebanon resident.