USB External Sound Card or Graphic Equalizer for Laptop?

My intention and goal are to use Musescore to compose music and then burn it to CD.

To do this, I need to control the volume. the bass and the trebles.

I have a G 72 HP laptop computer which I like quite a lot. Unfortunately, the sound quality isn't that great. To make up for this deficiency I have a speaker system consisting of one woofer and two trebles speakers.

The problem I have with the speakers is that I can't control the volume and the sound input. I can turn up the volume, but either the bass over powers the trebles or the trebles over the bass.

So I have been wondering which would help or solve my problem: an external USB sound card or a graphic equalizer? If possible, I'd like to keep this under $100. If this is not possible please let me know.

if anyone else has any other ideas how I can control the sound input on my speakers I would really like to hear them.

Sincerely,
Lafayette