Ok for your 18 inch screen put tehe screen size on 1280x960.
For the refresh rate set it at 65z ir 70hz.
Hit apply and see if windows will accept that and display correctly.
Read this link below, I don't think this work without you damaging something.
For your 32 inch put that 720p and read this guide and read near the bottom.
For the ati control panel, have it auto detech the second display and adjust accordingly so both are nearly matched up.
For the game itself choose 1280x720 window mode, keep the settings on medium.
Come back and let me know what happens.