I haven't had this problem with my own kids, but was a Kinder teacher. I had some students with fluid in their ears who had significant hearing loss that was relieved by treatment.
The positives in this is that you seem to have caught it early so treatment is more likely to be successful, and it was "late" enough in her development that her speech shouldn't be affected.
Try not to worry (easier said than done, I know), truthfully I've heard many stories like this that ended up being ok.
ADDED- just noticed you mentioned her speech problems, which could be alleviated if it's fairly recently acquired. If it's long term, she may have had hearing problems that stayed under the radar until now. In either case, the prognosis is excellent with some Speech Therapy.