The Marussia Formula One team's De Villota suffered life-threatening head and facial injuries in the accident at Duxford airfield in eastern England on July 3 and lost her right eye after undergoing emergency surgery.
Madrid's La Paz hospital, which also treated late golfing great Seve Ballesteros, said De Villota had undergone plastic surgery and treated by brain and eye specialists during the six days of her stay since returning from England.
The specialists "will continue to monitor her progress because she will need further treatment from time to time in the clinic," the hospital said.
De Villota did not need brain surgery but would be kept under observation, it added.
The accident occurred just after the 32-year-old had completed a straight-line aerodynamic test and was returning to mechanics when her car accelerated abruptly and slammed into a team truck at helmet level.