WPyogi on "Support Required on Responsive Theme"

Responsive is certainly a good theme - as to "best" - that's entirely subjective. No reason it would not work for a small business.

For any changes to theme files, you'll need to setup and use a Child Theme - you can find a free one on the theme's dedicated support site here: http://cyberchimps.com/forum/free/responsive/

Many of the changes you want to make are made using CSS, so I'd suggest you start here:

https://getfirebug.com/

http://www.w3schools.com/css/default.asp

http://csscreator.com

For any more specific CSS help, you'll need to post a link to your site.