I wanted to get a letter of recommendation from my volunteer supervisor, but it seems she is no longer in that position. If she wrote the letter anyways, would it still count for something?
Sure, it would still count. People change jobs all the time, but it's more appropriate to get the letter from the person who supervised you at the time, than whomever is currently running the volunteer program. The only weird part might be her current title / position, which she could choose to include or omit on her letter.