1st Post, Welcome Aboard!

I would keep

Pioneer Receiver

Pioneer Speakers (level controls, yeah!)

sell Yamaha Speakers or use elsewhere or give away

New Cartridge with Headshell, Your tonearm has a removable Headshell, plan on moving the new cartridge to a better Turntable later so the improvement/investment is transferrable

My favorite not very expensive Moving Magnet Cartridge (works with your receiver’s phono input) is:

Audio Technica Headshell/Cartridge Combo Kit

VM540ML/H

includes a headshell (keep your old cartridge/headshell/factory aligned) for when you get a better turntable you can put the current one back on, sell old TT or use elsewhere or give away).

It has a MICROLINE Stylus shape, much better sound and lasts longer than others.

Adjust the level controls of those speakers for your listening space.

How old are your ears?

I cannot post links, but you can find and read this article

sound-smith dot com /articles/stylus-shape-information

everyone,

long term advice is great, however OP's budget is being ignored.

"for my budget (+/- a few hundo)."

people are not paying attention

either to OP's budget (+/- a few hundo)

or his existing speakers, I looked them up

go to hifishark, check the prices asked for his Pioneer HPM-100 Speakers 

what the hell do you think would be better for a few hundro????

these speakers have Level Controls, giving the ability to adjust for both the space and OP's preference.

The receiver/tt/speakers certainly would reveal the improvement of a new cartridge, AND, the investment of a new cartridge can be moved to a new TT when ready.

Save money for quite a while before looking for better speakers