how i can turn off the left column or is there any way to modfiy the theme and make the left col in its orginal place ?
You can turn off the left column by going to Admin / Features (tiki-admin.php?page=features) and checking "Layout per section" . Then when you click on "Admin layout per section" you can uncheck the left column in whatever Tiki sections you don't want it to display.
I think putting the left column in its normal place would make the center column very narrow. Well, either on the left or right, having two side columns plus the center column in a theme that has left and right margins as well makes things rather tight, at least on a 1024px-wide screen. But I'll work on a few variations of the theme as soon as I can — probably a full-width version with three columns and a narrow-width version with two columns, left modules stacked under right.