Work on one problem at a time. Make sure the fuel leak is repaired. Then clear the DTC's and perform a drive cycle
http://www.obdii.com/drivecycle.html to make sure no other DTC's pop up. Then select "I/M Readiness" on a scan tool, it will show the status of each monitor. Make sure all monitors have completed their tests. If/when the P0440 comes back, we can deal with diagnosing and repairing it.