Job: Convert Modern Car Dealer to Helix

I NEED the gmodstore addon 'Modern Car Dealer | Showcases, Mechanic, Underglow, Easily Configurable' configured to be compatible with a Helix-derived game mode. Right now what I can assume is the 'buy' button says 'nil' because it isn't checking for the proper currency. I can pay more than $20 and potentially pay you for more projects if you want to cooperate with me on a slightly higher level. Urgent request! Thanks.