How to pamper an aging hamster?

[Lauukin]

My little Robo Melonberry is about 2.5 years old, and is starting to show more and more signs of aging. She has lost some weight and looks a bit dingy and patchy. She still runs a little bit, and climbs and generally seems to have decent energy, but its obvious she's getting older and slower. I've been feeling so bad and I've been spoiling her with her favorite treats and all this, but I wanna know what else to do to make her happy in her later days. She was rather social with her cagemate Macha but due to work, caring for 2 hamsters was difficult so I adopted her away. They were sisters and super lovey and sweet, and I feel worse knowing she's all alone. Its a little late to get her a cage mate as well?