I'd look for a local rose society to find seeds. I'd stay far away from places like ebay unless you are VERY sure of the sellers credentials. Otherwise you could get seeds for almost anything else but roses. You might also ask your family, friends or neighbors to leave some hips on their roses to ripen for you.

Cuttings are a different story. If the rose is patented, legally you can not root cuttings of it. A rose patent last for 20 years so roses older than that can be grown from cuttings. If you can get some locally that would probably be best because shipping time and weather conditions could affect the success of rooting mailed cuttings.