Changing Fonts (and related settings ) In Wordpress

I am using wordpress for my blog/site. I am using Freshnews theme from woothemes as the theme for the blog.

Here is the link:

The font is not that good and it is way too small and the spacing is bad (too congested).

How do I change the fonts, size, spacing (line and paragraph) throughout the blog.

I know I would have to change it somewhere in the stylesheet. But where exactly and how?

And what are the ways to get this done?

Should I install a font somewhere?

Should I use webfonts (like google webfonts)?
What is the advantage in using this?

or what are the other ways?

You would change all of these things within your CSS and include the font replacement codes in the appropriate places such as header.php in the template folder.