Sorry, but I thought I had replied to this a few moments after you sent it yesterday. But now I don’t see my reply!! No idea what I did wrong (on my own web site too 🙁 ), but I was on my mobile phone, so thats probably the mistake.
Anyway, the answer is:
Go to your theme’s ‘theme.php’ file and find these two entries (near the bottom):
Change them to:
$WT_STATS_S_CHART_X = 550;
$WT_STATS_S_CHART_Y = 200;
I have now made this change in all the themes for the next release.