Brake upgrade

I ordered my hydration pack and received my rack for my truck, but now........

After riding my entry level Haro V1 for a couple weeks I am sure of one thing......I HATE my brakes. They are the simple cantilever brakes.
The Haro V1 is a 7spd.
To get a level better brake set-up about how much am I looking to spend?(if it is like $300 or more than I will just save for a new bike)
How do I know which styles are compatible?
Is this the upgrade to make or am I missing a more valuable one?

Maybe just new and better pads and cables??