Hellos everybody!

I have been searching for information to change the size of comment block but did not find any. Then modified the style.css file.
What I want is to adjust the size of comment block to 540px. In the mentioned css file changed:
1) comments-bubble add comments-form-bubble to 540px.
2) comment-text to 500px.
Want to resize because of limited width on the content page since the comment script is integrated. Very nice script!!!
It's working fine but the avtar is sitting on the top of the comment block and leaves empty place just to the right of the avtar.
Have also tried to float the texts or/and the avtar but with no luck. Can anyone help me with this? I will appreciate.