Replying to Boot Issues

Hi NS,
A few years ago I bought a pair of 2010/11 Scarpa spirit 4's used for $100 and they worked well when I was a less aggressive skier. Now that I'm a bit more aggressive and going on longer tours, they just are not comfortable, and I'm also not getting the performance I want. My biggest problem is that the shin section will not cinch down enough (I realized today that they are a few sizes too big and just had an insole in the liners, making them fit my feet). I was wondering if there is a way to fix this, or just to upgrade my boots. I just spent most of my budget fixing my bike so I couldn't buy something super expensive.
Thanks for your input!
(I apologize if this isn't in the right place, this is my first time posting)