Tweaks on template

I need to make some tweaks on the template for my blog. Where can I get guidance to do this? For example on the blog below I want to :

1. Get rid of the calendar image without the heading going off on a wander
2. Have all images sit above the text post (instead of being wrapped by text) and span the middle post column and be clickable to the original size.
3. Add tags and category at the end of the post.
4. Change the comment heading on the single post to a different font.

Any guidance (or tips on the specific things above) would be gratefully received!

My blog