Are you not satisfied with the fonts that is available for your blog? If so, you may want to check out
100 Legal Sources for Free (as in Beer) Fonts. I have not tried it as I am not a big fan of fancy fonts and is quite satisfied with what I have, so I cannot vouch for what is available in that site. But if you like fancy fonts, give that site a try.
As to how to use it, if you don't know, ask, perhaps I will answer with another post. That is for the future