combined modules shipping

Hi, I have 3 shipping method, 2 of the is extension (one of them: https://www.opencart.com/index.php?rout ... ckpackpont).
Can I combine them somehow, to change the shipping cost, depends from the total of the cart?
I mean: if Total<1000 HUF - the 3 method is 800 HUF; if total between 1000 and 5000 HUF - the 3 same method, but with difference prices (500, 600, 700 HUF), If the total>5000 HUF - free shipping only.
My problem is, that my two modules are extensions I already installed, using a selector maps, that I have to integrate to the shipping method.

Any idea, extension, custom coding, anything?

This Mod has been sold twice, so, who should know, exept for the Mod-Creator itself !?
Ernie