Add paragraph w/ tag list before posts and change page numbers to "Older posts"

Here’s my blog page at the moment: http://www.peterchamberlaincann.co.uk/blog/

I’d like to add a paragraph before the posts, with exactly the same formatting as the other pages, with the header “Blog” and a list of categories and tags that updates automatically.

I’d also like to change the page numbers at the bottom of the page to the “Older posts” button that it used to be on my .com blog: http://peterchamberlaincann.wordpress.com/blog/