Stalled Cider....I think
I am a first time home brewer. for context, I have an old Mr beer kit. The LME was long past its expiration, so I thought I would use the vessel to make a simple cider using some organic apple juice. I added a cup of sugar. and used safeale US 04 and some fermaid o. After a week everything looked like it was going well, but when I opened the lid to check on it I noticed some fruit flies nearby and became convinced that one of them had flown into my cider. at that point I racked it to a 1 gallon carboy so I can see it more clearly. Now it seems to be stalled. it had been a few days since racking when I went to check the specific gravity and it is sitting at 1.030. I did taste it and it seemed thin and still mildly sweet. I was trying to ferment it to dry.
so my question is, do I leave it and see what happens? do I add some more yeast and yeast nutrient and try to restart fermentation? I'm guessing that I left behind a lot of the active yeast when I racked it?
The original yeast I used was from a different beer kit that was also several years old. I now have some other options that I recently purchased.
Edit: looks like the consensus is that I need to pitch some more yeast and yeast nutrient. I have red star premiere classique or safeale us-05. Any thoughts on which might be better in this situation?