Gabrielle Giffords standing on her own

PHOENIX - Doctors say Rep. Gabrielle Giffords can walk a little and is even trying to improve her gait. But the report Sunday in The Arizona Republic adds the congresswoman herself is planning to "walk a mountain."

Giffords uses her left side and has begun making limited use of her right arm and leg, a common effect of a bullet wound on the left side of the brain, said Dr. Gerard Francisco, chief medical officer at Houston's TIRR Memorial Hermann who works with Giffords daily.

"Her left side is perfect," said Pia Carusone, her legislative chief of staff. "She can do whatever you can do."

She said that even in her wheelchair Giffords has stringent posture: tall, tight, strong — like always.

Complete coverage: Tragedy in Tucson

The Republic report — containing interviews over the past few days with her husband, doctors and others close to her — gives the latest picture of her recovery 15 weeks after a gunman opened fire in a Tucson parking lot, killing six people and wounding 13 others, including Giffords.

The physicians place her in the top 5 percent of patients recovering from her type of brain injury, the newspaper said.

"She shows a lot more independence right now," Francisco said. "She's her own person."

Though it's still not clear if she will be able to attend Friday's launch of the space shuttle, which will be commanded by her husband Mark Kelly, her rehabilitation has been progressing steadily.

Click on the video player below to watch an exclusive CBS News interview with Mark Kelly in which he tells Katie Couric about his wife's plans, and what he learned about her that he never knew before.

Nurse Kristy Poteet said Giffords pushes a cart up and down the hospital halls as therapy, focusing on using the correct muscles.

Poteet, who has worked with Giffords since she arrived in Houston on Jan. 21, said more therapy comes from games of bowling and indoor golf.

Those close to her said Giffords speaks most often in a single word or declarative phrase: "love you," "awesome."

She longs to leave the rehab center, repeating "I miss Tucson." When that day comes, Giffords told Poteet she plans to "walk a mountain."

Dr. Dong Kim, the neurosurgeon who oversees Giffords' care, said most of the physical and speech recovery happens within nine to 12 months, but a patient's ability to think can improve for years.

There were hopeful language signs even on the March day that Giffords learned about the people killed during the Tucson rampage Jan. 8.

Kelly said he was reading a newspaper story about her out loud when she noticed he skipped a paragraph. He said he hadn't realized how well she could read.

That paragraph told of the casualties in the Tucson shooting — news that set Giffords grieving.

"So many people, so many people," Giffords repeated. Poteet said she would find Giffords with heavy looks on her face, repeating "no-no-no-no-no."

For that reason, Kelly said he hasn't told her that the victims included her friends and colleagues Gabe Zimmerman and Judge John Roll, or a 9-year-old girl, and three others, the kind of older constituents she loves to help.

Kelly said he wants her to be able to process the emotions without fighting so hard for the words.

"The challenge is she knows what she wants to say, and she knows everything that's going on around her," Carusone said, but can't always express it. "It's frustrating for her. She'll sigh out of exasperation."

The Republic reported that Kelly comes in the morning with coffee and the newspaper, heads to work at NASA, and returns to Giffords at night to talk through their days. Sometimes, he takes a nap with his wife in her hospital bed. It's a twin-size mattress, and so he holds her close.

When he comes into the room, Giffords breaks into an oversized smile, Poteet said, reaching out her good arm to beckon him to her side, give him a half-hug.

Though doctors have not yet approved the trip to Cape Canaveral for the shuttle launch, they said it should be safe.

"We're very comfortable with her traveling," said Kim.

Kelly, who has been to space before, said his job "will be a little bit harder this time, just because I want to look out for her."

He wants her in Florida but if she weren't there, "it wouldn't be the end of the world either."

Kelly will phone Giffords during the mission, but he expects the conversations will be different than on his last flight.

On "one of my last calls to her from space, she was walking from the Capitol back over to Rayburn (House Office Building) with Miles O'Brien from CNN."

Now, he will ask her "how things are going and how she's doing and what's her day like," he said.

They have a particular phone goodbye, "but that's a secret," he said.