Changing Blog Title And Description

When I installed wordpress with fantastico in the site name and description box I put my domain name in site and my main keyword in description.Once I installed, in general settings I tried to change title and description but it will not change.How can I change that to reflect my blog title instead of my domain name and I want more of a description for my site than just the keywords.Apparently I should not have added domain name and keyword in the site and description box when installing.