Save my Gerberas

Hello everyone,
I am very new to this forum and require some hel immediately if not sooner. I was given a pot of Gerberas for m birthday in May and they have been doing fairly well until lately.
Before I go any further I must tell you that they are being tended t indoors and will continue to be since I don't have any outdoor space. have North West exposure and gets the most sunlight as the Sun move west.
I want to keep them, but the leaves have powdery spots on them and i looks like brown patches are to follow. Until now two red flowers hav repeatly come through, but now there is a third. I have a feeling should re-pot them, but I would like to get opinions before doing so. want to do it this week, so please could anyone offer up some advice.
Many thanks,
-- Hematite
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