Copy paste this in excel and it will give you your new score.
Use C1 for your old score
C2 for the strength of the field (the first game of the league this will be 1500 and slowly this will raise and by the end of the league this will be somewhere over 1600, you can deduct this from last game you played).
C3 for the position you reached in the tournament and
C4 for the number of entries.