Magic

At first I thought I'll have to leave it for rendering for couple of hours with at least 10000 samples to reduce noise from those sparkles, untill I came with some idea.
I noticed that those sparks gives light instead of tons of noise when they're the only source of light. So I separated those lights behind her and those sparks into separate layers and then created two render layers which use those lights separately and then combine it when it's done. And that's the result. Instead of probably 2 days rendering with 10000 samples and probably still lots of noise I've done it in 4h with 500 samples for lights behind her and 2000 for light from sparks.
It's some magic.

I didn't even had to use 3rd party programs. It's just Blender.

Well... I've resized it from 125x full hd to 100x full hd for minor noise reduction (this noise on her skin comes from specular map. So it's not a noise technically).