This is my way of connecting Donna Noble to the newer seasons, and has definite spoilers for A Good Man Goes To War, so do not read this unless you have seen that episode or already spoiled yourself.

Updated one section below to be more consistent with what was revealed in that episode.

Donna-Temple Noble went missing on August 19, 2012, and was never seen again. After many months of a massive search effort, it was deemed hopeless and she was officially declared dead. She seemed to have vanished completely into thin air.

Her grandfather, Wilfred Mott, even tried to find and contact the Doctor despite the possible danger to Donna's health, but was unable to locate him. Some of his former companions were contacted, but none of them had any information that could be of any use as they hadn't heard from the Time Lord either. He never saw him again for the rest of his life, and died roughly two years later, not knowing what had befallen his precious granddaughter.

The truth, which was only known by a select few, and by the Doctor himself much later... is that the missing woman was a victim of a Weeping Angel. Due to her metacrisis, which while locked away was still very much a part of her, it was drawn to her as if she was a shining beacon, overflowing with energy. It was too good of an opportunity to resist.

She stood no chance. All it took was one touch of the Angel's hand as she was out for a morning walk, and she was gone, displaced many years backwards in time. But there was a rather interesting and terrible side-effect for the Angel itself, as the metacrisis energy it had taken from her was highly incompatible, reducing it to a pile of dust upon the sidewalk.

And thus, Donna-Temple Noble did as most others in her situation did, and made a new identity and life for herself. She never told anyone of what happened, because she knew that nobody would believe her. She kept her first name of Donna, and on a whim decided to choose the last name of Reeve, as she had appeared in the past in a graveyard and it was on the first headstone she read. It was rather fitting, as her old life was over and she was about to start a new one.

She missed her husband, mother and granddad, and spent many nights crying herself to sleep over her loss. But over time, she married and produced a son. Sadly, when said son was just five years old, she suddenly died of an unknown complication and was found to still be tightly clutching her head in death. Her autopsy showed there to be massive brain hemorrhaging and trauma, but the cause was never discovered.

Her son went on to have a son of his own, one Rory Williams, who later became the friend and husband of Amy Pond. Though appearing to be normal under all circumstances, dormant Time Lord DNA was present in his body and mind. He often saw things that others didn't, was a fast learner, and ever since hearing Amy's stories of the Doctor when they were still children something clicked within his soul. Once he met him in person, it was as if he had always known him, but he couldn't explain why or how. The same was true when he stepped foot into the TARDIS for the first time.

Rory and Amy's daughter, Melody Pond (or River Song as she was later known as) inherited her father's Time Lord DNA and due to her two parents traveling in the TARDIS together for an extended period of time, and having been conceived in proximity to the Time Vortex itself, most of it was active within her body making her a partial Time Lady herself.

Much later, when the Doctor had finally heard word of Donna's disappearance, he dropped everything and immediately went after his lost best friend. Amy, Rory and River were along for the trip, and the Doctor quickly explained to the three about her. River already knew about Donna, and the painful truth that was about to be revealed to them, but stood silent.

If River Song doesn't say "Spoilers!", then she's serious.

Rory, being his usual astute self, mentioned to the Doctor that his grandmother's name was also Donna, and that she died when his father was still a child and thus had never met her. The Doctor was stunned, thinking that it just couldn't be possible... could it?

He decided to go back to the day she officially went missing, to start. It was very tricky for the four to hide from her, and they had almost been caught a few times. They were some distance behind, when Amy saw something that shook her and made her scream in terror.

It was only a quick glimpse, but she knew she saw a Weeping Angel.

The Doctor realized that Rory's statement was gaining further ground. Donna had gone back in time, and after another quick trip (asking Rory what year his grandmother died, and then going back a year before that), his suspicions were confirmed when he saw the woman he knew to be Donna Temple-Noble and a young boy in a park. There was nothing that anyone could do, as it was a fixed event in time and two of his three companions would never exist if he changed anything.

Back in the present day, the foursome visited the grave of Donna Williams. River suggested that the Doctor should be left alone for a while, and after tenderly hugging him and saying that she wished she would have known her great-grandmother, the three left him alone and silent at Donna's headstone.

"Oh, Donna.." he said, and tears escaped from his eyes as he placed a bouquet of flowers below. They were not native to Earth, and in fact only existed on one planet over ten million years ago, but they were her favorite. He only wished that she would be around to chide and slap him for cohorting with her great-granddaughter, but knew it would never be so.

And so, Donna's story has come to an end, but not before beginning many more.