Showing/hiding fields upon variations select

Hi
I want to be able to add conditional logic to the product page (frontend) upon variations select, is there any plugin for this?
For example, if a user chose variation#1, two fields opens, if he chose variation #2, third field is open etc.
I did something myself in the page I provided, but the client wants more complicated selecting and conditional logics, and I try to shorten the way with a plugin.

Thanks in advance!

The page I need help with: [log in to see the link]