Once you move, could you get her a buddy?
When I had to rehome my 4 piggies I had great success finding them a loving home using this site: Guinea Pig Home Listings - Main Index
(you could also use it to find her a buddy whenever you're ready). :) My four pigs were all older, the oldest was 5 and the youngest was barely 3, they found a great home together (with a C+C cage and "the right" food!), within a few months of being listed.
I miss them SOOO much but I know they're loved and the guys that adopted them (a gay couple) let me visit them whenever I want, which makes it better.
Just keep in mind that your piggy is a herd animal. She's not going to think of you as another piggy and therefore isn't going to be as happy as she could be with a buddy. I think, if you pay a lot of attention to her, she could do ok. But she won't be great.
I'm not trying to be a huge downer, but I have had some expierence with lone guinea pigs and it's never been fun. For instance, my male piggy, while we were waiting for him to be 6 months old so he could be nuetered (his mom happened to be preggo when I brought her home, so he was alone from 4 weeks to 7 months). He would talk 24/7 unless someone was holding him. I ended up making him a kind of sling so that we could carry him around all the time and keep him calm. He was never really happy unless we were carrying him. He had to be alone while everyone was out of the house, at work/school, and it was the saddest thing when we'd come home after being away for 5-6 hours and see him stretching his little body to get to us, wheeking like a wounded baby bird. It wasn't normal wheeking either, it was urgent "I neeeeeeeeeedddddd you!!!" wheeking. It was a lot of emotional turmoil too. It was like having a baby or child that needs constant attention, care, and emotional investment. There was never a moments break. It was hard leaving the house because he'd start wailing as soon as I'd put him down; it was hard coming home because I'd feel like a dang jerk if I just ignored his calls but it was extremely tiring holding him close continously.
Once he hit 6 months and was nuetered (it takes about a month for "the baddies" to die, hahaha), then introduced to my girls at 7 months, his personality brightened SO much. He just blossomed being around those of his own kind. He still loved me to death, but his ladies had a bigger hold on his heart than I ever could, and that was good! I had figured that he was probably just fine with just my family and I for companionship but once I saw him with his ladies, I knew I was wrong. Even though I was giving up every waking moment to be his friend and to keep him company, it still wasn't enough to fufill his needs.
*hugs* I know this is a hard decision, and I'm so sorry for your loss of your other little one. I'm not trying to make you feel bad, at all, I'm just trying to share my expierence. :) I'm sure you'll do what's best for her, after all, you know her, I don't! :)