Custom Header

[Saahilk2000]

I was hoping someone could guide me how to make these changes.

I want to put a customer header for my website and it is slightly large in dimensions (because i wanted it that way) but if i put it on the left side, it overlaps the logged in user info and if i put it on the right, it overlaps the search button.

Is there any way to increase the space assigned so that if the logo is large, these fields would move down slightly, automatically? I am using SMF 2.0.2, default curve theme.