Thank you for the photo of the mark. There is no photo of the set, but this tells me what I need to know.
This is Arlen China of Seyei, Jpapan in pattern number 575, named the Ultimate pattern. The design should be crisp, white china with a raised flourish rim trimmed in gold, bronze or a platinum enamel paint glaze. The design is from 1953 to 1968 when it was discontinued. This design, unlike some of their others , remains subtle and classic enough to still fit easily into today's decors.
Your options are to sell the set on Ebay separated into sets of twelve dinner plates, 12 bowls, 12 salad plates, etc. if you have the time and patience for it. I can advise you on pricing, shipping and packing if that is how you decide to sell the set. Most people don't have the time or energy to do that. If you were to sell on Ebay, the dinner service would get about $400, cups and saucers 150.00, and $15 to $35 each for any serving pieces (cake plate, tureen, open vegetable dishes, etc).
Your other option is to find a local auction house in your area and consign the set. They would see the set for you and 14 to 45 days later you would get a check for the hammer price minus their 10 to 20 percent commission. Let me know your nearest large city and I can give a recommendation. Keep in mind that the whole set might only bring $200 to $400, but you are not having to do much work for it.