First, the simple one regarding avatars.
This link will help (FAQs) but I also know that the place to put the avatars is rather diffficult to find, so go to the user cpu and go to edit options and scroll all the way down. There you will have the option to change an avatar.
To find a thread in the forum, use the search function at the top right corner of the page. Or, if you wanted to do it the old fashioned, harder way, scroll to the bottom of the forum. On the bottom right there should be numbers that are links. These are the number of pages that this particular forum has. Just click through them until you find your topic.
Hope it helps!
Istawen