Kuddos to you for taking care of a bun that is disabled. You sound like a wonderful caregiver for your bun and I'm sure that she appreciates you giving her such good care.
Listen, if you are considering getting another bun for company, there are a few things that you need to take in to consideration prior to doing this. First, you may want to get a bun that has been altered. This can help a great deal with certain behaviors towards your current rabbit. Second, if your rabbit has not been altered, you are going to have to understand that even if she is disabled, she may display certain behaviors such as mounting and other dominant behavior towards another rabbit. Introduction needs to be slow and I wouldn't suggest leaving a new rabbit unsupervised with your current rabbit due to her disability. In other words, do not house them together in the begining.
I once had a rabbit that had splay leg. She was a sweet rabbit. She required alot of care because of her disability and not being able to clean her bum as good as healthy rabbits. I had her for two years before she passed away.
Good luck with what ever decision you make!
25 yrs experience with rabbits - mommy to 3 netherland dwarf rabbits - Vet Tech