(NewsCore) – Rep. Gabrielle Giffords (D-Ariz.) will step down from Congress this week, she announced in a video message to her constituents on Sunday.

Giffords has been recovering from a brain injury suffered last January when she was shot in the head after a gunman opened fire at a public meeting she was holding in a Tucson supermarket parking lot.

“I have more work to do on my recovery, so to do what is best for Arizona I will step down this week,” Giffords said, speaking slowly but clearly in the video message posted on YouTube. “I’m getting better. Every day, my spirit is high. I will return and we will work together for Arizona and this great country.”

Six people were killed and thirteen people, including Giffords, were wounded in the rampage.

During her first televised interview in November with ABC News’ Diane Sawyer, Giffords indicated that she wanted to return to Congress when she was “better.” She has been undergoing rehabilitation treatment in Houston.

According to the Arizona Daily Star, Giffords will submit her letter of resignation later this week to House Speaker John Boehner (R-Ohio) and Arizona Gov. Jan Brewer. The newspaper said Brewer will set a date for the special election to fill Giffords’ seat for the rest of her term.

Before leaving office, Giffords is expected to attend President Barack Obama’s State of the Union address on Tuesday in Washington, the Star reported. Citing the congresswoman’s staff, the Star said Giffords will also meet privately with some of the people who attended the “Congress On Your Corner” event that was interrupted by the deadly shooting last year.

On Jan. 8, the one-year anniversary of the event, Giffords led the Pledge of Allegiance at a candlelight vigil at the University of Arizona to honor the victims and survivors.

Her husband, retired astronaut Mark Kelly, spoke at the ceremony, reading out the names of the dead and declaring, “We remember their spirits and the joy each of them brought to us.”