comments box size

Hi, Thanks for a great theme! can you help me with these 2 issues? 1 I wanted to change the height of the "leave a reply" box. Its too big as of now. 2. above and below the comments and replies, there is lot of space, which makes the comment boxes very big. Is there a way to compact the comments/replies boxes?(reduce the height that is) my website: http://www.rajivagarwal.net/to-kill-or-not-the-mosquito-dilemma Thanks!