Here's a link to the sub woofer: https://amzn.to/3x0KAAr
Here is a link to the speakers. Yes, you'll need at least two: https://amzn.to/3e9h2Yq
Maybe dump the budget audio/TV head unit while you are at it. IT'S ONLY MONEY! Here's something you may like by Marantz for $2,500. You have that much in your left pocket: https://amzn.to/3gcqKw4
Today, there are many audio and video options. For some it's a matter of price and others space. If you are an audiophile, a good stereo or AV system is worth the price of entry.