Need some answers on ductwork?

i have cats that have gotten under the house and tore all the ductwork up i dont no how bad i just kow we have not ran the system for a long time now and dont have the money yet to fix it is there a way i can do a quick fix like going under the house and seeing how bad a possible using tape if they are not to bad and some of the vents have been covered do to repair of floors is there a way i can tie those of i have an infant and it is like 20 degrees now out side we do have heaters but it sucks using them knowing you have a huge system