Kitchen exhaust fan? I am remodeling and have my original wall mount range hood and exhaust fan to deal with.?

The fan motor and fan are mounted on my roof, the fan motor has only about 1000 hours on it. I need a new hood, controls, lights and liner etc in the kitchen, the cabinetry is covered. Will I be able to find an insert that I can wire to the existing fan or will I have to have something custom made? I will be checking out Menards and Home Depot later today and no the original company that made my fan is no longer in business.