I agree with AlpineRaven2. As long as the lens is a Minolta AF mount, it should work, whether it's Minolta, KM, Sigma, Tamron... Ebay is one place to look for lenses, as well as local used shops. B&H Photo carries used and new equipment. KEH.com is another one. I bought a 70-210 Minolta lens for well less than $200 off ebay. It's in great shape.
Welcome to PhotoCamel!
Elaine