You can fix that with a lot of things, like Compression, equalization ,limiting and more.
Now there are a number of ways you can go about "Isolating the Snare" so you can effectively tweak the sound. (And how you want to tweak it depends on the sound you want and the genre)
1. Duplicate your Track with the FX on the Insert(Which would be EZD and whatever else)
Now open up EZD on your original track, and take the Snare Mic levels down all the way(and click on the snare and select NONE as the sample) and on the duplicated track take down everything but the snare mics and set every other instruments sample to NONE that way on the overhead and room mics you don't have anything else interfering with the sound of the snare. (set the overhead and room mics to your liking, or all the way down) and now you can add whatever you want to that track on the insert(the FX bus) to change the sound, like compression and eq to fatten it up or whatever else you want. It's up to you.
I won't bother listing other methods , that should be sufficient for you.