BETTY DOOLEY'S apartment belonged to the proverbial old lady who never drove it off the city streets.

An oval living room like the White House, 10-foot high ceilings, beautiful woodwork, two fireplaces, a block or so off Connecticut Avenue near Dupont Circle -- sale price $59,000 -- it's the mythical apartment that everyone wants but few find.

Dooley's story points out that such places still do exist. Such old buildings often have more room, architectural interest and soundproofing than some new ones. But you have to be lucky, and you have to know what you're doing. You may not want to buy charm at the price of bad plumbing.

In 1916, when the Altamira apartment house was built, just off Connecticut, Dooley's three rooms and pantry kitchen were only a fourth of an immense apartment that once had multiple bedrooms, libraries, kitchens and such. The original apartment's kitchen is now an entire efficiency. Her bedroom was once the library, and her kitchen, the butler's pantry. The original architect was Arthur Heaton; the owner, Col. George Truesdell. The building was converted to cooperative ownership in 1947.

"When I bought the apartment in 1978," said Dooley, "it belonged to an old lady who hadn't done anything to it for a good many years. So I was able to buy it at a real bargain and have all the work done to suit myself.

"Many people don't like coopeatives because they generally take a bigger down payment than a condominum. But usually the condominums have already been remodeled. I was able to save money by choosing what decorating and repair work I wanted to do."

Dooley figures she spent about $12,000. The first thing she did was to hire Maurice Blum, an interior designer she met at a party. "I decided right away that we could work together," she said. "I knew from the beginning I wanted a decorator. In Texas, I think most people do work with one. Some people think you give away the right to your own taste when you hire a decorator, but that's not so.

"I just don't have the expertise to tell how a little scrap of paper will look on a wall. Maury knew not only all of that, but he had the sources to find what we wanted at a bargain. But I certainly didn't relinquish my say-so on what it should finally look like."

Using a decorator also doesn't mean you have to buy all new furniture. Blum worked with Dooley on an hourly rate. She used mostly the furniture she had brought with her when she came here from Texas in 1970. Only a lamp, a Chinese box used as a table, the chandelier and the living-room light fixture, two hassocks and a Vanleigh Lucite coffee table are new.

Dooley had the floor sanded, the ceiling painted, the walls papered and the bedroom carpeted, as well.

The color scheme throughout is blue and white.

As in many interiors of the period, the walls had panels of wallpaper, framed with an agreeable molding scraped off.

For the living room, Blum chose Fantan, a Judd Scott wallpaper with an orderly Chinese design of palm fronds fans, which seem to complement the shape of the room. The curtains are sheer and fit within the windows to show off the nice woodwork.

In the dining room, another paper called "Anna Mae Wong" is obviously Chinese movie star inspired. The dining room furniture and chairs and the rug are also Oriental contemporary. The macrame valance over the windows are by California artist Russell Wendroff. The fireplace is a cheerful note.

Dooley acquired the metal-frame sofas in the living room and dining room when she was living in Texas and a furniture-company owner owed her money. One exactly fits a niche in the dining room. Blum had the sofas recovered and the dining-room rug chosen for her previous apartment. The brass chandelier holds candles -- she buys them from Purcell's church supply company so they won't drip on guests. Blum gave her a long-handled snuffer, also from a church-supply company.

The Peter Max poster is a souvenir from when she met the artist after working on the Mondale campaign. She bought the Art Nouveau bowl on the living-room table from an antique show in Cincinnati on the same campaign.

The bedroom is furnished like the library it once was, with a fine old pine secretary and charming curved Victorian sofas in front of the pleasant fireplace.

Some of the paintings are by her daughter, Melissa Dooley. Her son, of all things, has a catfish restaurant seating 600 people in Texas and a catfish farm on the Amazon River.

Dooley started in politics working on a Texas committee to repeal the poll tax; later she was a lobbyist in Austin. She came to Washington with Robert Stauss and set up the legislative program for the committee on National Health Insurance. For the past few years she hs been executive director of the Women's Research and Education Institute, the research arm of the Congressional Women's Caucus. The office studies the economic problems of older women and works on women's issues with graduate students with the Women's Center at George Washington University and with congressional women and staffs. The institute has received grants from the Rockefeller and Ford foundations.

After the apartment was finished, Dooley had it blessed by Father Henry Bruel, rector of St. Thomas's Episcopal church. The choir she belongs to sang, and 100 people crowded in. Dooley's twin sister, Jane Roberts Wood, wrote a poem for the occasion. Dooley hopes to have it carved on her bedroom mantelpiece. Wood's poem begins: I'd bless this house in my own way. I'd take it back to Texas, if I could . . . But it ends with: Still in these rooms there's a good vibration. A blessing makes a house a celebration.