Citation FO pay will vary greatly depending on company size / location. I believe a young, relatively low time-typed FO would start in the $25-35K range, but again, thats just from other companies I know that fly Citations.
Citation 500 series should pay around $50,000 for an F/O with your time. Remember, if you don't get it up front, you'll never get it. If they can afford the airplane, they can afford to pay you enough to live.