where did you get the coordinates? are they from database or must be calculated on the fly in your drawing routine? see, the coordinate information needs to be used in two places and those two places run asynchronously, you'd better separate this code out so you can reuse it
do you know index.aspx runs first? how could it get your returnObject?? you can try to put in a session variable and refresh index.aspx, but you can only get the previous value