Batch of design problems

I'm glad that I found the best WordPress theme there is. Unfortunately, I need a bit of help to make it exactly the way I want it to be. I'll list my problems and then provide a screenshot, that highlights where the problems are, to give you a better idea of them.

1. I want to change the background color of the search box and it's font color to something else.
2. I want to get rid of the two weird white bars that appear at the top and at the bottom (not in the screenshot) of my posts, or just change their color to something dark, possibly the same color as my main site.
3. Even though I put that image with a transparent background in my post, it showed up with a white background there. How can I fix it?
4. I'd like to get the text to appear next to the image, while being in the center of it. Also, possibly about 10px right from it.

Screenshot.

I'd be extremely grateful if someone could help me with these 4 problems that I have.