Add a BLOG to a current website

Hi there I am looking to add a blog section to a current web site. Blog needs to have easy posting function with video and picture upload and positioning left, right or centre of the post when required. Needs to have a twitter feed showing the last 3 posts with a C2A to Follow Us on Twitter. Needs to Have the same for Facebook Fan page with Click Like to follow us on Facebook.

Blog need to have 3 categories as well.

Also need to have the background image changed to reflect a Christmassy Theme..

Good luck...

Stevie