Centurion le mans/mavic cosmos

Longtime forum follower, first time poster!

My roommate bought a new bike last year and he past on his old Centurion le mans 12 speed steel bike with down tube shifters. When he was still riding the bike a car hit him and the wheels were bad. I rode them tolerable for a while, and then they got worse beyond repair. Since that one went bad I am stuck riding my mountain bike for everything. I am desparately trying to save money so i myself can buy a new road bike, so i don’t want to sink loads of money into the centurion. I would prefer not spending money on components that cannot be utilized should I purchase a new bike.

In my naivity and excitement to get the road bike up and running for the upcoming season, I found and purchased a pair of mavic cosmos at a GREAT price. Unfortunately do to the deatails in which it was purchased, I cannot return or resell the wheels. After removing the rear cassette of the former wheel I learned the unfortunate fact that the cassette is a traditional threaded freewheel on a traditional threaded hub, with the cassette freewheel hub on its way.

So I was wondering if anyone had any ideas. Can the cassette be retro fitted to the hub? Do I have to purchase a brand new cassette then chain, then crank, then shifters or can this work without spending anymore money?