I'm not sure how to answer because I don't want to insult your skills. But, with that risk, I'll suggest that the hardest part of video is audio. You didn't say what you used for the recording so I will guess it was a camera or camcorder with a built in mic. Those work of a lot situations, but stage performances are not one of them because the mic is too far from the source.
The only way you can get get audio from a stage is by getting mics on the performers. If the production company does that for the audience, you need to get the feed from the sound system.
Can you make lemonade from the lemons with audio? Not very well. You've found the Audio Effects in Premier Elements. I don't know of, read about or heard of any plug ins that will sweeten the music. Plug in providers will tell you what host programs they are compatible with.
Adobe produces the incredibly complex program called Audition and there is the freeware program called Audacity. Each is intended to manipulate audio, but I doubt it will work for what you want. Premier Elements provides tools for taking the audio track out of the project for use in any other program. You can then put the audio track back in to the project. Syncing may be challenging.
There is no easy answer. Good luck!