The Dashboard is fully configurable. Moving Widgets around and changing their sizes is simple.
To resize a Widget, hover over the bottom right corner of the Widget. You should see your cursor change to the resize cursor. Click and drag the corner of the Widget until it is the size you want.
To rearrange a Widget, hover over the top of the Widget (by the title if that is displayed). You should see your cursor change to the move cursor. Click and drag the Widget until it is in the location you want.