There are 3 ways to do it:
1) The indicator has to generate display objects for the levels, then your EA has to extract the prices off these levels using double price = ObjectGetDouble(ChartID(),<Level>,OBJPROP_PRICE);
2) Or the indicator has to generate global variables for the levels, then your EA just needs to read from the global variables.
3) Don't use any indicator at all. Just code the logic of your levels into your EA. This way is the best.