Hmmm, if you have been hacked and this is a relatively untouched WordPress install, you might be better off just discarding it and starting over.
Generally, you would not be able to see the hack unless you FTP in and look at the actual files. Then, it becomes rather obvious.
Let's say you just want to retrieve your content...
As LakeRat has said, you need to find the log-in to the admin section of your WordPress site.
The directory that holds the admin dashboard and log-in in a standard installation of WP is called "wp-admin"
or, if it's in a subdirectory: yourdomainname.com/wordpressdirectoryname/wp-admin
If you can log in, you can use the WordPress export tools to export your text content. It will be clean.
Write down the plug-ins and template you used, so you can recreate your site. Then, just trash the existing site. You can use the one-click to install a fresh copy once the old one's gone. Let the one-click create a new database for you (and trash the old one from the inside the Dreamhost administration panel later).
Or, if you'd rather, you can run the cleaner scripts as suggested in those two threads Lakerat has suggested above. But, you need to spend a bit of time making sure you get everything. Then, upgrade your WP from its Dashboard.
Getting used to using WordPress:
The main things you will want to take a look at as an author are your posts (your blog articles) your pages (any static pages you may have, "About" is the sample one from WP) your widgets (things that run in your sidebars) and your menus (drop down links to sections of your site.
Keep it simple at first, so you are concentrating on your content and then, as you get more experienced, spend some time at wordpress.org researching plug-ins and reading the forums for ideas and advice, there.