Upgrading help required (2.2 to latest)

helo!
i have a three year old site with reasonable amount of blog posts and its running on wp 2.2. i am being constantly injected with the malicious trojan iframe and also for reasons of security et al, I need to upgrade my wp.

being a non-techie, what is the easiest way I could upgrade?

is it possible to make a clean fresh installation (which I find the easiest? no?) and point to the existing db tables, and get the site working?

any detailed advice or point to existing links I may bot have seen would be great!